Question

The cost of a car service is partly constant and partly varies with the time it takes to do the work. if cost 3500 naira for a 5 1/2 hour service and 2900 naira for a 4-hour service. Find the formula connecting cost, naira C with time, T hours, hence find the cost of a 7 1/2 hour service. find the formula connecting c and t using the elimination method

Answer 1

no answer!!!!!!!!!!!!!!!!!!!!!!!
please help me!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 2

C = r t + k

3500 = 5.5 r + k

2900 = 4 r + k

subtracting equations (to eliminate k) ... 600 = 1.5 r ... r = 400

substitute back to find k (the constant costs)