Risa has some balls in a bag. The number of balls is less than 20. If she gives 3 balls to each pupil, she will have none left. If she gives 7 balls to each pupil, she will need 20 more balls.
- How many pupils does Risa have?
- How many balls are there in the bag?
(a)
Total extra number of balls that Risa will need = 20
Number of extra balls that Risa will give to each pupil
= 7 - 3
= 4
Number of pupils that Risa has
= 20 ÷ 4
= 5
(b)
Number of balls that Risa has
= 3 x 5
= 15
Answer(s): (a) 5; (b) 15