At a game stall, each child needed 3 coupons to redeem a gift, while an adult needed 7 coupons. Given that 2/3 of the people who redeemed gifts with their coupons were children and total of 1248 coupons were collected by the gam stall, how many adults redeemed their gifts?

Answer 1

so, if there were x adults and 2x children, we have
7x + 3*2x = 1248
now finish it off