Question

Marcia can make 5 candles in an hour. Kevin can make only 4 candles in an hour, but he already has 7 completed candles. Explain to Marcia how she can use a system of equations to determine when she will have the same number of candles as Kevin. Use complete sentences.

Answer 1

Represent hours by h.
Marcia: 5h
Kevin: 7+4h

Answer 2

m(h)=5h

that is marcia's number of candles where she makes 5 candles per hour (h)

kevin makes 4 but already did 7 so

k(h)=4h+7

when will they have same number of candles?

when will m(h)=k(h)

set equal

5h=4h+7

minus 4h from both sides

1h=7

answer is 7 hours

system of equation is

m=5h

k=4h+7

find what value of h makes m=k true

answer is 7 hours