Question

23. The number which when subtracted from each of the terms of the ratio 19:31 reducing it
to 1:4 is
(a) 15
(b) 5
(c) 1
(d) none of these
24. Daily earnings of two persons are in the ratio 4:5 and their daily expenses are in the ratio
7:9. If each saves 50 per day, their daily earnings in are
(a) (40, 50)
(b) (50, 40)
(c) (400, 500) (d) none of these
25. The ratio between the speeds of two trains is 7: 8. If the second train runs 400 kms. in 5
hours, the speed of the first train is
(a) 10 Km/hr (b) 50 Km/hr (c) 70 Km/hr (d) none of these​

Answer 1

Hi dear!

23. The number which when subtracted from each of the terms of the ratio 19:31 reducing it

to 1:4 is

(a) 15✔️

(b) 5

(c) 1

WHEN WE SUBTRACT 19 AND 31 BY 15 WE GET...

19 - 15 = 4

AND

31 - 15 = 16

SO,

4:16

Can be written as

1:4

So,

15 is correct

Answer 2

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Let the number being subtracted be x

Then, (19-x):(31-x) = 1:4

-----> 19-x/31-x = 1/4

-----> 4(19-x) = 31-x

-----> 76-4x = 31-x

-----> 76-31=4x-x

-----> 3x = 45

-----> x = 45/3

-----> x = 15

Therefore, the number is 15.