# 4 boys and 3 girls spent 120 Rs. on the average, of which boys spent 150 Rs. on the average. Then what would be the average amount spent by the girls is :

4 boys and 3 girls spent 120 Rs. on the average, of which boys spent 150 Rs. on the average. Then what would be the average amount spent by the girls is :
[A]60 Rs.
[B]80 Rs.
[C]90 Rs.
[D]100 Rs.

80 Rs.
Total expenditure $= 120 \times 7 = 840\ Rs.$
Total expenditure of 4 boys $= 150 \times 4 = 600\ Rs.$
Total expenditure of 3 girls $= 840 - 600 = 240\ Rs.$
∴ Their average expenditure $= \frac{240}{3} = 80\ Rs.$
Hence option [B] is correct answer.