Question

Speed of train A is 250 km/hour. The speed of train B is 25% more than the speed of train A.
I) Find the speed of train B
II) Find the ratio of the speeds of the two trains
III) What fraction of the speed of train A is the speed of train B?




please explain also so that I could understand easily

Answer 1

Hi!

Here is the answer to your question.

 

Let the speed of the freight train = xmiles/hour

And, speed of express train = y miles/hour

Given, speed of express train = 2 × speed of freight train – 30 miles/hour

∴ y = 2x – 30

⇒ 2x – y = 30  … (1)

 

Distance covered by express train in 2 hour = Distance covered by freight train in 2 hours + 40 miles

 ∴ y miles/hour × 2 hours = x miles/hour × 2 hours + 40 miles

⇒ 2y =2x + 40

⇒ –x + y = 20    … (2)

Solving (1) and (2), we get



When x = 50,

–50 + y = 20     (from (2))

⇒ y = 70

Speed of the freight train = x miles/hour = 50 miles/hour

Speed of express train = y miles/hour = 70 miles/hour

 

Cheers!

Answer 2

speed of train A = 250km/hr
l) speed of train B =(25% of A) + A
= (25/100)× 250

= (250/4)+A
= 62.5 +250
=312.5

ll) ratio train A:train B
= 250/312.5
=0.8
= 4:5

lll) let fraction be x
so, 250x = 312.5
x= 312.5/250
x= 1.25
x= 5/4
thus 5/4 is the fraction