Hi,
I'll start the discussion going with Q9.
10% ==> 5 girls.
100% ==> 50 girls.
Now it's easy to find the number of boys at first yes.
Thanks!
Cheers,
Wen Shih
Originally posted by Ashleeann hannah:1. During a sales promotion,customers will get a 200ml packet of milk free for every 1litre carton of milk purchased. If Mrs Lin needs to buy 10 litres of milk, how many 1-litre cartons of milk must she buy?
2. 1 kg of fish cost as much as 3/4 kg of prawns. Eliza paid $60 for 2 kg of prawns and 4 kg of fish. What is the cost of 1kg of prawns.
3. Mr Lin had a carton full of yellow balls and blue balls. If he removed one yellow ball and one blue ball together each time until no yellow balls were left in the carton, the number of blue balls remaining was 100. If one yellow ball and three blue balls were removed together each time until no blue balls were left in the carton, the number of yellow balls remaining was also 100.
Find the total number of yellow balls and blue balls in the carton.
4. Two barrels A ans B contained different amounts of water at first. Some water from A was poured to B so that the amount of water in B was doubled. Then, some water from B was poured to Aso that the amount of water in A was doubled. After these pourings, the barrel each contained 20 litres of water. How many litres of water were in the Barrel A at first?
5. Tom and Jerry each has a sum of money. Tom's amount is 3/5 that of Jerry's. If Jerry gives Tom $150, his remaining amount will be 7/9 that of Tom's. How much does Tom have?
6. Mr Tortoise crawled from Dover Woods to Kent Forest at 7.30 am. An hour later, Mr Rabbit left Dover Woods for Kent Forest and caught up with Mr Tortoise at 9.00 am. Mr Rabbit reached Kent Forest at 10.30am. What time did Mr Tortoise reach Kent Forest if both of them travelled at a constant speed and took the same track?
7. A group of tourists visited an amusement park. The admission ticket cost $15 per adult and $10 per child. They paid a total of $620 for the admission tickets. If the ratio of the number of adults to the number of children was 5:8,find the number of children in the group?
8. A red cube is completely filled with yellow cubes of the same type. Each yellow cube has a volume of 64 square cm. Each yellow cube is completely filled with identical green cubes. The ratio of the length of the sides of the red cube to the yellow cube to the green cube is 6:2:1. How many cubes are there altogether?
9. There were 120 children in a church choir at first. When the number of boys increases by 20 and the number of girls decreases by 10%, the number of children in the choir became 135. How many boys were in the choir at first?
Tks :D
Q1.
For every 1L bought, 200ml will be given free. Hence, she will have 1.2L instead of 1L.
1L + 200ml = 1.2L
10L / 1.2L = 8 and 1/3 packets, which should be rounded up to 9 packets.
Q2.
Since 1kg of fish cost as much as 3/4kg of prawns, 4kg of fish will cost as much as 3 kg of prawns.
Hence, 2kg of prawns + 3kg of prawns = 5kg of prawns cost SG$60.
1kg of prawns cost $60/5 = $12.
Q3.
A model diagram will be needed for this question. I will explained it later if no one else does so.
Q4.
Not enough information. I could be mistaken though, given that I am on flu medication now.
Q5.
Another model diagram question.
Q6.
A speed-time line will be good for this question.
Amount of distance travelled by tortoise in 1 and a half hour will be amount of distance travelled by rabbit in half an hour.
Mr rabbit took 1 and a half hour to travel the same distance as what will take the tortoise 4 and a half hours.
Hence, Mr tortoise will reach kent ridge at 9am + four and a half hours = 1.30 pm.
Q7.
Another model diagram question.
Cost of tickets for 5 adults = $15 X 5 = $75.
Cost of tickets for 8 children = $10 X 8 = $80
Total cost = $155
Amount of sets of 5 adults and 8 children = $620/ $155 = 4 sets
Amount of children = 4 sets X 8 = 32 children
Q8.
Amount of red cube = 1 red cube.
Using the ratio to compare,
Amount of yellow cubes = 3 X 3 X 3 = 27 yellow cubes
Amount of green cubes = 2 X 2 X 2 = 8 green cubes
Total amount of cubes = 27 + 8 + 1 = 36 cubes.
Q9.
10% of girls = 5 children
Amount of girls at first = 5 X 10 = 50 children
Amount of boys at first = 120 - 50 = 70 boys.
Originally posted by wee_ws:Hi,
I'll start the discussion going with Q9.
10% ==> 5 girls.
100% ==> 50 girls.
Now it's easy to find the number of boys at first yes.
Thanks!
Cheers,
Wen Shih
Lecturor, I will leave Q3, 4 , 5 to you. I just eaten my medication and need to go take a rest already. Please help to correct any mistakes I might have made, as I am feeling pretty dizzy right now.
Hi,
Do take good care. Am having a flu :P
Cheers,
Wen Shih
4. Two barrels A ans B contained different amounts of water at first. Some water from A was poured to B so that the amount of water in B was doubled. Then, some water from B was poured to Aso that the amount of water in A was doubled. After these pourings, the barrel each contained 20 litres of water. How many litres of water were in the Barrel A at first?
Hi
Use working backwards, you should be able to get 25 litres for barrel A in the beginning.
Play around, A --- 25 , B --- 15 , then A --- 10 , B --- 30 and finally, A --- 20, B --- 20
Have fun
Originally posted by baiyun:4. Two barrels A ans B contained different amounts of water at first. Some water from A was poured to B so that the amount of water in B was doubled. Then, some water from B was poured to Aso that the amount of water in A was doubled. After these pourings, the barrel each contained 20 litres of water. How many litres of water were in the Barrel A at first?
Hi
Use working backwards, you should be able to get 25 litres for barrel A in the beginning.
Play around, A --- 25 , B --- 15 , then A --- 10 , B --- 30 and finally, A --- 20, B --- 20
Have fun
Thank you baiyun for the correction. I just had my dinner, and is feeling better after some medication.
On a side note, it seems that a lot of people are down with flu lately, I just hope it has nothing to do with H1N1. Get well soon too, Mr Wee.
Q3.
Blue l__l__l__l = > 3 units
Yellow l__l__l = > 2 units
Since there are 100 more blue balls than yellow balls, 1 unit = 100 balls.
Total number of balls = 5 units = 5 X 100 = 500 balls.
Q5.
Tom l__l__l__l__l__l__l
Jerry l__l__l__l__l__l__l__l__l__l__l
Tom has 3/5 as much as Jerry.
If Tom gives Jerry $150,
Tom l__l__l__l__l__l__l__l__l__l
Jerry l__l__l__l__l__l__l__l
Hence, 3 units = $150, and 1 unit = $50
Amount that Tom has = 6 units = 6 X $50 = $300
thank you so much,i was really stuck when i encountered all this probelm sums.
now i understand,thank you.
Hi Ashleeann hannah
Do you have the answer for Q8?
8. A red cube is completely filled with yellow cubes of the same type. Each yellow cube has a volume of 64 square cm. Each yellow cube is completely filled with identical green cubes. The ratio of the length of the sides of the red cube to the yellow cube to the green cube is 6:2:1. How many cubes are there altogether?
1 +27 +216 --- 244 cubes
Originally posted by baiyun:Hi Ashleeann hannah
Do you have the answer for Q8?
8. A red cube is completely filled with yellow cubes of the same type. Each yellow cube has a volume of 64 square cm. Each yellow cube is completely filled with identical green cubes. The ratio of the length of the sides of the red cube to the yellow cube to the green cube is 6:2:1. How many cubes are there altogether?
1 +27 +216 --- 244 cubes
Thanks for the correction again, really major mistake here.