STUCK ON HOMEWORK?

Question

Question

P6 Mathematics

Question post on Tue, 23/01/2018 8:44pm

Last.year peter was.five times as old as his son roy..given that their total ages now are 38 years. How old will peter be when he is thrice as.old as his son ?

Answer

Khong Pek Mao · Answer 1 · Post on Tue, 23/01/2018 9:40pm

This is a Before After question.

	Before	Transfer	After	now
Peter	5u	+1	5u + 1	31
Son	1u	+1	1u + 1	7
Total	6u		6u + 2

6u + 2 = 38

6u = 38 – 2 = 36

1u = 36 ÷ 6 = 6

6 + 1 = 7

5u = 5 × 6 = 30

30 + 1 = 31

7 + 5 = 12

31 + 5 = 36

UmaPraha · Answer 2 · Post on Tue, 23/01/2018 10:47pm

UmaPraha Post on Tue, 23/01/2018 10:47pm

Last two steps 7 + 5 can you exp ?

Khong Pek Mao · Answer 3 · Post on Wed, 24/01/2018 8:14am

I simplified it by using trial and error method.

Now 7 31

1 year 8 32

2 years 9 33

3 years 10 34

4 years 11 35

5 years 12 36

Alternatively, you may use the cross multiplcation method.

(7 + 1u)/1 = (31 + 1u)/3

21 + 3u = 31 + 1u

3u – 1u = 31 – 21

2u = 10

1u = 10 ÷ 2 = 5

Alternatively, you may use the Difference method.

31 – 7 = 24

2u = 24

1u = 24 ÷ 2 = 12

12 – 7 = 5 years

31 + 5 = 36 years old

alfretztay · Answer 4 · Post on Wed, 24/01/2018 6:29am

Last year —
Peter : 5 units
Roy : 1 unit

5 + 1 + 6
6 units + 2 = 38
1 unit = (38 – 2)/6 = 6
5 units = 30

Now —
Peter : 31
Roy : 7

7 x 3 = 21
31 – 21 = 10
10/2 = 5
5 + 31 = 36

Ans : 36 years old.

ConceptualMaths · Answer 5 · Post on Tue, 23/01/2018 11:47pm

Last Yr Now ? Yrs later

P 5u 5u + 1 3p

R u u + 1 p

5u+1+u+1 = 38

6u = 38 – 2

= 36

1u = 36÷6

= 6

Difference btw P and R = 4u

= 24

2p = 24

1p = 12

Peter’s age = 3p

= 3 × 12

= 36 (ans)

UmaPraha · Answer 6 · Post on Wed, 24/01/2018 5:54am

UmaPraha Post on Wed, 24/01/2018 5:54am

Unit part method . Got it