3. If s varies directly as (r + 1) and s = 8, when r = 3, calculate the value ofr when s = 20. (4marks)

When s = 20, r = 9

Step-by-step explanation:

Given,

s is directly proportional to (r + 1)

s = k(r + 1)

(k is the constant of proportionality)

When s = 8,

8 = k(3 + 1)

8 = k(4)

8 = 4k

8/4 = k

2 = k

When s = 20,

20 = 2(r + 1)

20 = 2r + 2

20 - 2 = 2r

18 = 2r

18/2 = r

9 = r

h who knows

step-by-step explanation:

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