Pri 6 maths problems sums 2
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...Hi bro and sis...me (lxlim) againI have some maths problems to ask all of you...please help me with the problem.
1)Jane had 40 more dresses than Susan.When Susan gave Jane 36 dresses,Susan had 1/5 of the total number of dresses Jane had. How many dresses did Jane have at first?
2)Mrs Chen is 36 years old.Her husband is 8 years older.How old was Mr Chen 5 years ago?
3)All the chairs in a school hall can be arranged in stacks of 7or in stacks of 13.There ara less than100 chairs in the hall.How many chairs are there?
4)What is the last digit of 273 to the power of 120?
Thanks for your help!
LXLIM
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1) Let the no. of dresses susan has be x
so Jane's no. of dresses is x+40
after susan gives jane 36 dresses,
susan --> x-36
jane --> x+40+36
--> x+76
since susan has 1/5 of jane's, you can form this equation,
(x-36)5 = x+76
5x - 180 = x+76
4x = 256
x = 64
jane --> x + 40
--> 64 + 40
--> 104 #
2) Mr Chen's age currently --> 36 +8 =44
5 years ago --> 44-5 = 39 #
3) 13 x 7 = 91 #
Note: I don't know the correct working, i think it has something to do with factors.
4) Don't be affected by the large number. If you look carefully, there is a pattern.
273 to the power of 120 means
273 X 273 X 273 ......... (120 times)
since the qn ask for last digit, just take the last digit to multiply
3 X 3 X 3 X 3 .......(120 times)
You will see a pattern
3 X 3 = 9
9 X 3 = 27
27 X 3 = 81
81 X 3 = 243
243 X 3 = 729
729 X 3 = 2187
2187 X 3 = 6561
6561 X 3 = 19683
The pattern of the last digits are, 3,9,7,1,3,9,7,1.......
So each group contains 3,9,7,1
there are 4 "things" in the group, so you take 120/4 = 30
30 is a whole number, which means the last digit is 1 #
IMPORTANT!!
In other cases, if they ask other numbers which you may not get a whole number. You may get remainders, remainder of 1, 2, or 3 which corresponds to the last digit of 3,9,7 respectively. 1 is when there are no remainders.
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Originally posted by Name?:
1) Let the no. of dresses susan has be x
so Jane's no. of dresses is x+40
after susan gives jane 36 dresses,
susan --> x-36
jane --> x+40+36
--> x+76
since susan has 1/5 of jane's, you can form this equation,
(x-36)5 = x+76
5x - 180 = x+76
4x = 256
x = 64
jane --> x + 40
--> 64 + 40
--> 104 #
2) Mr Chen's age currently --> 36 +8 =44
5 years ago --> 44-5 = 39 #
3) 13 x 7 = 91 #
Note: I don't know the correct working, i think it has something to do with factors.
4) Don't be affected by the large number. If you look carefully, there is a pattern.
273 to the power of 120 means
273 X 273 X 273 ......... (120 times)
since the qn ask for last digit, just take the last digit to multiply
3 X 3 X 3 X 3 .......(120 times)
You will see a pattern
3 X 3 = 9
9 X 3 = 27
27 X 3 = 81
81 X 3 = 243
243 X 3 = 729
729 X 3 = 2187
2187 X 3 = 6561
6561 X 3 = 19683
The pattern of the last digits are, 3,9,7,1,3,9,7,1.......
So each group contains 3,9,7,1
there are 4 "things" in the group, so you take 120/4 = 30
30 is a whole number, which means the last digit is 1 #
IMPORTANT!!
In other cases, if they ask other numbers which you may not get a whole number. You may get remainders, remainder of 1, 2, or 3 which corresponds to the last digit of 3,9,7 respectively. 1 is when there are no remainders.
Ths for your help,NAME? !!
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Originally posted by Name?:
1) Let the no. of dresses susan has be x
so Jane's no. of dresses is x+40
after susan gives jane 36 dresses,
susan --> x-36
jane --> x+40+36
--> x+76
since susan has 1/5 of jane's, you can form this equation,
(x-36)5 = x+76
5x - 180 = x+76
4x = 256
x = 64
jane --> x + 40
--> 64 + 40
--> 104 #
2) Mr Chen's age currently --> 36 +8 =44
5 years ago --> 44-5 = 39 #
3) 13 x 7 = 91 #
Note: I don't know the correct working, i think it has something to do with factors.
4) Don't be affected by the large number. If you look carefully, there is a pattern.
273 to the power of 120 means
273 X 273 X 273 ......... (120 times)
since the qn ask for last digit, just take the last digit to multiply
3 X 3 X 3 X 3 .......(120 times)
You will see a pattern
3 X 3 = 9
9 X 3 = 27
27 X 3 = 81
81 X 3 = 243
243 X 3 = 729
729 X 3 = 2187
2187 X 3 = 6561
6561 X 3 = 19683
The pattern of the last digits are, 3,9,7,1,3,9,7,1.......
So each group contains 3,9,7,1
there are 4 "things" in the group, so you take 120/4 = 30
30 is a whole number, which means the last digit is 1 #
IMPORTANT!!
In other cases, if they ask other numbers which you may not get a whole number. You may get remainders, remainder of 1, 2, or 3 which corresponds to the last digit of 3,9,7 respectively. 1 is when there are no remainders.
PSLE maths students do not learn expansion, equation and solve for x lah.
PSLE maths students do not know what is the power of 120 lor and question 4 What is the last digit of 273 to the power of 120? is not a real PSLE maths question lor.
Some months ago in homework forum, someone posted a maths question that uses RELATIVE VELOCITY and claimed that it is a PSLE Maths lor. LOL.
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Hi
Hope this helps.
Best wishes
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Originally posted by Lxlim:...Hi bro and
sis...me (lxlim) again
I have some maths problems to ask all of you...please help me with the problem.
1)Jane had 40 more dresses than Susan.When Susan gave Jane 36 dresses,Susan had 1/5 of the total number of dresses Jane had. How many dresses did Jane have at first?
2)Mrs Chen is 36 years old.Her husband is 8 years older.How old was Mr Chen 5 years ago?
3)All the chairs in a school hall can be arranged in stacks of 7or in stacks of 13.There ara less than100 chairs in the hall.How many chairs are there?
4)What is the last digit of 273 to the power of 120?
Thanks for your help!
LXLIM
1) 4/5 -> 36
5/5 -> 5/4 x 36 = 45
45+40=85
ANSWER : 85
2) 8-5 = 3
3+33 = 36
ANSWER : 36
3) 13 x 7 = 91
ANSWER : 91
4) WTF? I dont even get this in Maths Olympiad
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Ths for your help!Originally posted by baiyun:Hi
Hope this helps.
Best wishes
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Originally posted by baiyun:
Hi
Hope this helps.
Best wishes
wa kaoz sibei zai ! i see great effort here... up for u !