Question

The total cost of 2 identical cups, 3 identical plates and 1 bowl is $116. The total cost of 3 such plates and the bowl is $64. The cost of 1 cup is twice as much as the cost of 1 plate. What is the total cost of the 3 plates?

Answer 1

c = 2p
3p+b = 64
2c+3p+b = 116

so 3p = $39

Answer 2

Let the cost of cups = c
Let the cost of plates = p
Let the cost of bowl = b
Equation 1
2c + 3p = 1b = $116
Equation 2
3p + 1b = $64
Equation 3
1c = 2p
* In equation 2
3p + 1b = $64
1b = $64 - 3p
b = $64 - 3p
* Substitute; equation 3 and equation 2 in equation 1
Equation 1: 2c + 3p + b = $116
2 (2p) + 3p + ($64 - 3p) = $116
4p + 3p - 3p = $116 - $64
4p/4 = $52/4
p = $13
The cost of one plate is $13
Total cost of 3 plates = $13 * 3 = $39