A set of Children’s blocks contains 3 shapes: longs, flats, and cubes. There are 3 times as many longs as cubes, and 30 fewer flats than longs. If there are 600 blocks in all, how many long’s are there?

Answer:There are 126 longsStep-by-step explanation:Let's represent the number of longs by l, number of flats by f and number of cubes by c.We are told that there are 600 blocks in all.This implies l + f + c = 600We also know that there are 3 times as many longs as cubes: this meanc = 3lThere are also 30 fewer flats than longs.This mean f + 30 = l I.e f = l - 30We now have 3 equations to solve simultaneously l + f + c = 600 ...........(i) c = 3l................(ii) l -30 = f...............(iii)We can substitute equations iii and ii into Il + l - 30 + 3l = 6005l - 30 = 6005l = 630l = 630/5 = 126.