Question

An 84 cm wire is cut into three pieces the second piece is 4 cm long the first piece and the third piece is twice as long as a second piece find the length of the shortest piece 

Answer 1

C

Explanation:

let the first piece be k cm long

so rhe length of the second piece is k+4 cm

the length of the third piece is 2(k + 4) cm

so, the first piece is the shortest and is equal to

84 = (k + k+4 + 2k+8)

84 = 4k+12

so k = 72÷4

= 18

Answer 2

C

Explanation:

let the shortest piece be x then the second piece is x + 4 and the third piece is

2(x + 4) = 2x + 8

sum the 3 pieces and equate to 84

x + x + 4 + 2x + 8 = 84

4x + 12 = 84 ( subtract 12 from both sides )

4x = 72 ( divide both sides by 4 )

x = 18

that is the shortest piece is 18 cm