There are 24 students in 7a class. During a youth brigade they planted a total of 24 birches and roses where every girl planted 3 roses each and every three boys planted 1birch. Find how many birches and roses are planted from the students of 7a?
Ratio of birches to roses is 1:3. Every single event plants 4 flowers. 24/4 = 6 events. 6 events x 3 roses planted/event= 18 roses planted. Same goes for the birches.