The graph is misleading because the year’s interval is not constant.
The first year to the second year, the gap is 1 year; in the second to the
third year, the gap is 2; in the third to the fourth year is 4; and the fourth
to the fifth year is 6.
1. Eyeballing the data, the best fit will be pretty close to a line between the leftmost point and the rightmost point.
We estimate those points as (4,220) and (28,470)
The point point form for a line joining (a,b) and (c,d) is
(c-a)(y-b) = (d-b)(x-a)
(28 - 4)(y - 220) = (470 - 220)(x - 4)
24(y - 220) = 250(x-4)
24y - 5280 = 250x - 1000
24y = 250 x + 4280
y = (250/24) x+ (4280/24)
Approximately that's,
y = 10.4 x + 178
Answer: 4th choice, 10.4x + 180
2. For 48 wheelbarrows,
y = 10.4(48)+180 = 679.2
Answer: 679.2 liters of sand
See https://web2.0calc.com/questions/help_29603.
3 pairs of choices give rise to 2^3 = 8 possibilities:
.. bus, full, morning
.. bus, full, afternoon
.. bus, concession, morning
.. bus, concession, afternoon
.. train, full, morning
.. train, full, afternoon
.. train, concession, morning
.. train, concession, afternoon
