The number of blue markers is four times the number of yellow markers. The number of yellow markers is 5 more than the number of brown markers. The total number of markers is 133. The cost of each blue marker is $4.40 and the cost of each brown marker is $1.70. The total cost of all the markers is $490.60.

1. Find the number of brown markers.
2. Find the cost of a yellow marker.

(a)
Number of brown markers = 1 u
Number of yellow markers = 1 u + 5

Number of blue markers
= 4(1 u + 5)
= 4 u + 20

Total of number of markers
= 1 u + 1 u + 5 + 4 u + 20
= 6 u + 25

6 u + 25 = 133
6 u = 133 - 25
6 u = 108

1 u = 108 ÷ 6 = 18

Number of brown markers
= 1 u
= 18

(b)
Number of brown markers = 18

Number of yellow markers
=  18 + 5
= 23

Number of blue markers
= 4 x 23
= 92

Cost of brown markers 
= 18 x 1.70
= $30.60

Cost of blue markers 
= 92 x 4.40
= $404.80

Cost of yellow markers
= 490.60 - 404.80 - 30.60
= $55.20

Cost of 1 yellow marker
= 55.20 ÷ 23
= $2.40

Answer(s) (a) 18; (b) $2.40