the charge c of a telephone company is partly constant and partly varies as the number of units called u,the cost of 50 units is 2500 and the cost of 120 units is 3000.find

Question

the charge c of a telephone company is partly constant and partly varies as the number of units called u,the cost of 50 units is 2500 and the cost of 120 units is 3000.find
the formula connecting c and u,
u when c=4000

oobleck · Accepted Answer

c = a + bu
You have
a + 50b = 2500
a + 120b = 3000
Solve for a and b, and then find u when
a + bu = 4000

Or, notice that b increased by 500 when u increased by 70
So, if c increases by another 1000, u will increase by another 140.

Honey · Answer

Very correct I got it in my lesson thank you very much I will introduce my brothers and sisters to it thank you very much

Luper · Answer

Yevhemba

Adekunle olaoluwa · Answer

Thank you