If R = xS⁴, when S = 5 and R = 6, then find value of R when S = 8?

39.3

20.5

32.8

52.4

R = xS⁴

When S = 5, R = 6

So,

6 = x × (5)⁴ = x × 625

⇒ x = 6 / 625

Now find R when S = 8:

R = (6 / 625) × (8)⁴ = (6 / 625) × 4096

= 24576 / 625 = 39.3216