Answer: The cost of dress is $20 and belt is $3
Equation's created:
1) 5d + 4b = 112
2) 3d + 2b = 66
Here 'd' is dress and 'b' is belt
Make 'd' subject:
In equation 1:
⇒ 5d + 4b = 112
⇒ 5d = 112 - 4b
⇒ d = (112 - 4b)/5
In equation 2:
⇒ 3d + 2b = 66
⇒ 3d = 66 - 2b
⇒ d = (66 - 2b)/3
Solve them simultaneously:
(66 - 2b)/3 = (112 - 4b)/5
5(66 - 2b) = 3(112 - 4b)
330 - 10b = 336 - 12b
-10b + 12b = 336 - 330
2b = 6
b = 3
Now find the value of dress:
d = (66 - 2b)/3
= (66 - 2(3))/3
= 20
