C

hi, need help with this maths problem. Thank you!

C

hi, need help with this maths problem. Thank you!

sushi88

Standing Broad Jump Shuttle Run

Queuing At first 7u 4u

18 from SBJ to SR -18 +18

Then the queues are equal, this implies

7u-18 = 4u+18

3u = 36

u =12

Hence queuing at SBJ was 7u = 84 and queuing at SR was 4u = 48

At the end, both stations have (84+48) = 132 pupils with each 66 pupils.

mr.tan

Thinking:Ratio is Jump:Run = 7:4. So we can use 7u:4u, a total of 11u. After some movement they become equal, i.e. divisible by 2. But 11 is not divisible by 2, so let's scale up by 2 instead. We use Jump:Run = 14u:8u with a total of 22u (so 22u/2 = 11u).Working:JUMP RUN BEFORE 14u 8u (total of 22u students) AFTER 11u 11u (3u students moved) So 3u = 18 and u = 6.Thus at the start, there are 14 x 6 = 84 students in standing boardjump queue and 8 x 6 = 48 students in shuttle run queue.At the end, there are 66 students in both queues.Checking:

JUMP RUN BEFORE 84 48 AFTER 66=84-18 66=48+18 (18 students moved)

mr.tan

Regarding the working you cancelled out, it can also be made to work: JUMP RUN BEFORE 7u 4u AFTER 7u-18 4u+18 They are equal at the end, so 7u-18=4u+18 => 3u=36 => u=12. It gives the same answer: JUMP RUN BEFORE 7x12=84 4x12=48 AFTER 84-18=66 48+18=66