let

h = the number of crayons Hunter has

m = the number of crayons Mike has

hunter has 7 times as many crayons as mike

h = 7m

if hunter gives mike 15 crayons they will have the same amount:

h - 15 = m + 15

by solving the system of equations:

h = 7m

h - 15 = m + 15

we find:

h = 35 crayons

m = 5 crayons

click here to see the step by step solution of the system of equations:

h + m = 35 + 5 = 40

together they have 40 crayons.