Question

Formular
V=a+bu
Question
P is partly constant and partly varies as q, if q is 5, p=20 and when q is 8, p=26
A. Find p when q =4

Answer 1

To find the linear equation that relates p and q, we can use the given data points (5,20) and (8,26).

Let P = a + bq

Substitute the values of (5,20) into the equation:
20 = a + 5b

Substitute the values of (8,26) into the equation:
26 = a + 8b

Now, we solve for a and b by solving this system of linear equations.

From the first equation, we get:
a = 20 - 5b

Substitute a into the second equation:
26 = 20 - 5b + 8b
26 = 20 + 3b
3b = 6
b = 2

Now, substitute b back into the first equation:
a = 20 - 5(2)
a = 20 - 10
a = 10

So, the equation relating p and q is:
P = 10 + 2q

Now we can find p when q = 4 by substituting q = 4 into the equation:
P = 10 + 2(4)
P = 10 + 8
P = 18

Therefore, when q = 4, p = 18.