The number of red staplers is thrice the number of purple staplers. The number of purple staplers is 10 more than the number of yellow staplers. The total number of staplers is 135. The cost of each red stapler is $3.70 and the cost of each yellow stapler is $1.80. The total cost of all the staplers is $425.70.
- Find the number of yellow staplers.
- Find the cost of a purple stapler.
(a)
Number of yellow staplers = 1 u
Number of purple staplers = 1 u + 10
Number of red staplers
= 3(1 u + 10)
= 3 u + 30
Total of number of staplers
= 1 u + 1 u + 10 + 3 u + 30
= 5 u + 40
5 u + 40 = 135
5 u = 135 - 40
5 u = 95
1 u = 95 ÷ 5 = 19
Number of yellow staplers
= 1 u
= 19
(b)
Number of yellow staplers = 19
Number of purple staplers
= 19 + 10
= 29
Number of red staplers
= 3 x 29
= 87
Cost of yellow staplers
= 19 x 1.80
= $34.20
Cost of red staplers
= 87 x 3.70
= $321.90
Cost of purple staplers
= 425.70 - 321.90 - 34.20
= $69.60
Cost of 1 purple stapler
= 69.60 ÷ 29
= $2.40
Answer(s) (a) 19; (b) $2.40
