Question

a purse contains rs.1,50 paise and 25 paise coins by number in the ratio 3:8:16. if the total value of all the coins be rs.605;find the number of each type of coin.

Answer 1

Let x be the proportion constant of the ratio, i.e, 3x:8x:16x <--This is the proportion of number of coins of each value.
Multiplying the coin values with the respective coefficient of proportion, we get:
(1*3x)+(0.5*8x)+(0.25*16x)=605
3x+4x+4x=605
11x=605
=> x=55
Now to find the total number of coins of each value we multiply x with the coefficient of proportion;
Number of:
1 ruppee coins= 3x=3*55=165
50 paise coins= 8x=8*55=440
25 paise coins= 16x=16*55=880

I hope that helps!

Answer 2

Given 
the ratioe of no.of coins of Rs1 . 50ps, 25ps = 3:8:16
no of irs coin be 3x
no.of 50ps coin be 8x
and no of 25ps coins be 16x
total value of Rs1 = 1× 3x = 3x
total value of 50ps = 50× 8x ps = (50×8x)/100 rupees = 4x
total value of 25ps = 25×16ps = (25×16)/100 rs = 4x
total amount = 3x +4x +4x 
which must be equal to 605
3x+4x+4x = 605
11x = 605
x = 55
no.of irs coin = 3x = 3×55 = 165
no.of 50ps coins = 8x = 8×55 = 440
no.of 25ps coins = 16x = 16×55 = 880