Question

The cost of soup, s, varies directly with the number of cans, c. When c is 4, the cost is 3$. Which graph represents the cost of soup?

Answer 1

S=3/4c since when c=4, s must equal 3

Answer 2

Answer:

Here,

s represents the cost of soup and c represents the number of can,

Also, s varies directly with c,

⇒ s ∝ c

⇒ s = kc -----(1)

Where, k is the proportionality constant,

Given, when c = 4, s = 3,

From equation (1),

$3=k(4)$

$\implies k=\frac{3}{4}$

Again from equation (1),

$s=\frac{3}{4}c$

Let x-axis represents the number of can and y-axis represents the cost of soup,

For graphing :

$s=\frac{3}{4}c$ is a straight line

Where, s ≥ 0 and c ≥ 0 ( cost and number of cans can not be negative )

When, c = 0, s = 0,

When c = 4, $s=\frac{3}{4}\times 4=3$

When c = 8, $s=\frac{3}{4}\times 8=6$

When c = 16, $s=\frac{3}{4}\times 16=12$

Thus, the line $s=\frac{3}{4}c$  is passing from the points (0,0), (4,3), (8,6) and (16,12).