STUCK ON HOMEWORK?

Question

Question

ATM82517

P6 Mathematics

Question post on Wed, 17/05/2017 9:02pm

pls help. thank you

Answer

alfretztay · Answer 1 · Post on Wed, 17/05/2017 10:21pm

total distance ——- 7u

2u ——- 18 x 5 = 90

1u ——- 90/2 = 45

7u ——- 7 x 45 = 315

John’s speed ——- 315/5 = 63

David’s speed ——- 63 – 18 = 45

90/45 = 2

Ans : 2h.

ATM82517 · Answer 2 · Post on Thu, 18/05/2017 7:41am

ATM82517 Post on Thu, 18/05/2017 7:41am

hi Alfretztay, thanks.

alfretztay · Answer 3 · Post on Thu, 18/05/2017 1:56pm

alfretztay Post on Thu, 18/05/2017 1:56pm

Hi ATM 82517, welcome .

SAHMom · Answer 4 · Post on Wed, 17/05/2017 11:17pm

I thought the question is strange. David travelled 5/7 of distance in 5 hours so he would need another 2 hours to travel remaining 2/7 of distance (by proportion).

The question may have a 2nd part asking for something tougher like to calculate speed. You may want to check again.

ATM82517 · Answer 5 · Post on Thu, 18/05/2017 7:43am

ATM82517 Post on Thu, 18/05/2017 7:43am

hi sahmom, thanks

BigDevil · Answer 6 · Post on Wed, 17/05/2017 11:24pm

The 18 km/h is a distraction.

In 5 hour, David covered 5/7 of the distance.

5/7 -> 5 hour

1/7 -> 5 ÷ 5 = 1 hour

To cover the remaining 2/7, he would need 2 × 1 = 2 hours

ATM82517 · Answer 7 · Post on Thu, 18/05/2017 7:42am

ATM82517 Post on Thu, 18/05/2017 7:42am

hi bigdevil, thank you ur explanation.