The number of red markers is twice the number of green markers. The number of green markers is 9 more than the number of brown markers. The total number of markers is 139. The cost of each red marker is $4.20 and the cost of each brown marker is $1.90. The total cost of all the markers is $412.10.
- Find the number of brown markers.
- Find the cost of a green marker.
(a)
Number of brown markers = 1 u
Number of green markers = 1 u + 9
Number of red markers
= 2(1 u + 9)
= 2 u + 18
Total of number of markers
= 1 u + 1 u + 9 + 2 u + 18
= 4 u + 27
4 u + 27 = 139
4 u = 139 - 27
4 u = 112
1 u = 112 ÷ 4 = 28
Number of brown markers
= 1 u
= 28
(b)
Number of brown markers = 28
Number of green markers
= 28 + 9
= 37
Number of red markers
= 2 x 37
= 74
Cost of brown markers
= 28 x 1.90
= $53.20
Cost of red markers
= 74 x 4.20
= $310.80
Cost of green markers
= 412.10 - 310.80 - 53.20
= $48.10
Cost of 1 green marker
= 48.10 ÷ 37
= $1.30
Answer(s) (a) 28; (b) $1.30
