There are 60 black and grey stamps in Box F. There are 50 black and yellow stamps in Box G. The number of grey stamps in Box F is three times the number of yellow stamps in Box G. The number of black stamps in both boxes is the same.
- How many yellow stamps are there in Box G?
- Find the total number of black stamps in both boxes.
(a)
Number of grey stamps = 3 u
Number of yellow stamps = 1 u
Black stamps + 3 u = 60 --- (1)
Black stamps + 1 u = 50 --- (2)
(1) - (2)
3 u - 1 u = 60 - 50
2 u = 10
1 u = 10 ÷ 2 = 5
Number of yellow stamps
= 1 u
= 5
(b)
Number of black stamps in Box G
= 50 - 5
= 45
Number of black stamps in both boxes
= 2 x 45
= 90
Answer(s): (a) 5; (b) 90