Two-passenger-trains-A-and-B-450km-apart-start-to-move-towards-each-other-at-the-same-time-and-meet-after-2-hours-If-train-B-travels-8-7-as-fast-as-train-A-find-the-speed-of-each-train-

Question Number 60143 by pete last updated on 18/May/19

Two passenger trains, A and B, 450 km apart,

start to move towards each other at the

same time and meet after 2 hours . If train B,

travels \frac{8}{7} as fast as train A, find the speed

of each train .

Answered by tanmay last updated on 18/May/19

s p e e d o f t r a i n A = 7 v k m / h r s

s p e e d o c t r a i n B = \frac{8}{7} \times 7 v = 8 v k m / h r s

s o \frac{450}{7 v + 8 v} = 2

\frac{30}{v} = 2 \to v = 15 k m / h r s

s p e e d o f A = 7 \times 15 = 105 k m / h r s

s p e e d o f B = 8 \times 15 = 120 k m / h r s

Commented by pete last updated on 18/May/19

Thanks very much sir, but how is speed

of train A = 7 v k m / h r ?

Commented by tanmay last updated on 18/May/19

a n s w e r i s c o r r e c t o r n o t \dots

Commented by tanmay last updated on 18/May/19

i h a v e t a k e n s p e e d A = 7 v b e c a u s e i c a n c a c u l a t e

e a s i l y t o f i n d s p e e d o f B

7 v \times \frac{8}{7} = 8 v

y o u c a n t a k e s p e e d f o r A = v

s p e e d o f B = \frac{8}{7} \times v

\frac{450}{v + \frac{8 v}{7}} = 2

\frac{450 \times 7}{15 v} = 2

2 v = 30 \times 7

v = 105 k m / h r \to s p e e d o f A

105 \times \frac{8}{7} . = 15 \times 8 = 120 k m / h r s p e e d o f B

Commented by pete last updated on 18/May/19

Ow its correct, only wanted to get clarification

I understand now . Thanks gain .

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