Question

The table shows the cost of hiring a concrete mixer for up to 5 days.
1
2
Number of days
3
4
5
19
45
Cost in £
32
58 71
The cost of hiring the concrete mixer is made up
of a fixed charge and a daily charge.
(1)
(i) How much is the daily charge? £
(1)
(ii) How much is the fixed charge? £
Tota​

Answer 1

Answer:

i. daily charge = £13

ii. fixed charge = £6

Step-by-step explanation:

Number of days (x) | Cost in £ (y)

1 | 19

2 | 32

3 | 45

4 | 58

5 | 71

Using the given table, we can represent this situation with an equation in slope-intercept form, y = mx + b, where,

m = slope = daily charge

b = y-intercept = fixed charge

✔️Thus, using the coordinates of any two given pairs, say (1, 19) and (2, 32):

Slope (m) = ∆y/∆x = (32 - 19)/(2 - 1) = 13/1

Slope (m) = 13

Therefore daily charge = £13

✔️To find y-intercept (b), substitute (x, y) = (1, 19) and m = 13 into y = mx + b.

Thus:

19 = (13)(1) + b

19 = 13 + b

b = 19 - 13

b = 6

Therefore, fixed charge = £6

✔️Substitute m = 13 and b = 6 into y = mx + b to represent the function given for the situation:

y = 13x + 6