The cost of apples (y) and their number (x) are in direct variation.
∴ y ∝ x
∴ y = kx …(i)
where k is the constant of variation
i. When, x = 1, y = 8
∴ Substituting, x = 1 and y = 8 in (i), we get
y = kx
∴ 8 = k × 1
∴ k = 8
Substituting k = 8 in (i), we get
y = kx
∴ y = 8x …(ii)
This the equation of variation
ii. When,y = 56, x = ?
∴ Substituting y = 56 in (ii), we get
y = 8x
∴ 56 = 8x
∴ x = 56/8
x = 7
iii. When, x = 12, y = ?
∴ Substituting x = 12 in (ii), we get
y = 8x
∴ y = 8 × 12
∴ y = 96
iv. When, y = 160, x = ?
∴ Substituting y = 160 in (ii), we get
y = 8x
∴ 160 = 8x
∴ x = 160/8
∴ x = 20
| Number of apples (x) |
1 |
4 |
7 |
12 |
20 |
| Cost of apples (y) |
8 |
32 |
56 |
96 |
160 |
