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