Karen makes 5$ per hour babysitting and 12$per hour giving music lessons one weekend she worked a total of 18 hours and made 139$.how many hours did she spend babysitting

Answer 1

Let "b" represent the number of hours she was babysitting and "m" the number of hours she spent giving music lessons.

Then b + m = 18.

Also, the amount of money she made can be calculated by taking the number of hours she babysat (b) and multiplying by the amount she charged ($5/hr). Same with music lessons (number of hours x $12/hr)

So 5b + 12m = 139

Take the first equation and solve for m by subtracting b from both sides (m = 18 - b)

Since "m" is the same as "18 - b", plug in "18 - b wherever there is an "m" in the second equation.

5b + 12(18 - b) = 139 Now, multiply out, simplify by combining like terms and solve for b: