4 boys and 3 girls spent Rs. 120 on an average, of which boys spent Rs. 150 on the average. The the average amount spent by the girls is-

Answer: Option A

According to the question,
Average : 4B + 3G = Rs. 120
Sum : 4B + 3G = 120 × 7 = Rs. 840
Average : 4B = 150 × 4 = Rs. 600
Sum of girls = 840 - 600 = Rs. 240
Average of girls = $$\frac{240}{3}$$ = Rs. 80