Question

Luke buys 4 bolts and 6 washers for $2.20 and Holly spends $1.80 on 3 bolts and 5 washers at the same local hardware store. Determine the costs of a bolt and a washer.

Answer 1

Cost of bolts = x = $0.3

Cost of washers = y = $0.167

Explanation:

Let us represent:

Cost of bolts = x

Cost of washers = y

Luke buys 4 bolts and 6 washers for $2.20

Hence:

4x + 6y = 2.20....Equation 1

Holly spends $1.80 on 3 bolts and 5 washers at the same local hardware store.

3x + 5y = 1.80....Equation 2

Combining both Equations

4x + 6y = 2.20....Equation 1

3x + 5y = 1.80....Equation 2

Multiply Equation 1 by 3 and Equation 2 by 4 to eliminate x

12x + 18x = 6.6.....Equation 4

12x + 20x = 7.2.......Equation 5

Substract Equation 4 from 5

= 2x = 0.6

x = 0.6/2

x = $0.3

Solving for y

4x + 6y = 2.20....Equation 1

4 × 0.3 + 6y = 2.2

1.2 + 6y = 2.2

6y = 2.2 - 1.2

6y = 1.0

y = 1.0/6

y = $0.167

Cost of bolts = x = $0.3

Cost of washers = y = $0.167