GB-24-04-001 · Real-life linear graphs
A hire company models the cost C pounds for h hours by .
(a) Interpret the constant term in this model.
(b) Work out the cost for 20 hours.
Part (a)
Real-Life Linear Graphs (y = mx + c)
Application of related method — Booklet p. 79
Method
1) In C = mh + c, the y-intercept c is the fixed starting charge (when h =
0) and m is the rate per hour
2) Substitute h to find total cost
Worked Example (GB-24-04-001 · Part (a))
Interpret the constant term in this model.
1)
£30 is payable before any hourly charges.
Ans =
Fixed charge of £30.
Part (b)
Real-Life Linear Graphs (y = mx + c)
Application of related method — Booklet p. 79
Method
1) In C = mh + c, the y-intercept c is the fixed starting charge (when h =
0) and m is the rate per hour
2) Substitute h to find total cost
Worked Example (GB-24-04-001 · Part (b))
Work out the cost for 20 hours.
1)
2.3 × 20 + 30.
2)
£76.00
Ans =
£76.00