Karen makes $5 per hour for babysitting and $12 per hour giving music lessons. One week she worked a total of 18 hours and made 139$ that day. How many hours did she spend babysitting ?

Question

anonymous · Answer

you need to use a system of equations
b= babysitting
m= music lessons

anonymous · Answer

we know she worked 18 hours, so.... b+m=18

anonymous · Answer

we know how much she gets paid for each, and what she made...
12 for m
5 for b
so.... 139=5b+12m

anonymous · Answer

solve b+m=18 for either b or m... we'll choose b
b=18-m

anonymous · Answer

substitute that in for the second equation, 139=5b+12m
b=18-m
139=5(18-m)+12m

anonymous · Answer

139=90-5m+12m
49=7m
m=7

anonymous · Answer

since we know m... we can plug that into the easier equation, b+m=18
b+7=18
b=11

anonymous · Answer

so, since b=11 and m=7, we know that she babysat for 11 hours and gave music lessons for 7 hours

anonymous · Answer

thanks !
i gotcha now.

anonymous · Answer

cool, good luck

anonymous · Answer

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