ratio and proportion
Deepak BoraNewbie
The monthly pocket money of Ravi and Sanjeev are in the ratio 5 : 7. Their expenditures are in the ratio 3 : 5 . If each saves Rs.80 every month, find their monthly pocket money.
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Let the pocket money be 5x & 7x
Expenditure = pocket money- savings
∴ expenditure for ravi = 5x-80
expenditure for sanjeev = 7x-80
(5x-80) : (7x-80) = 3:5
Cross multiplying
5(5x-80) = 3(7x-80)
25x-400 = 21x- 240
4x = 160
∴ x = 40
∴ pocket money for Ravi = 5x = 5×40 = Rs. 200
Sanjeev = 7x = 7 × 40 = Rs. 280