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Jeremy mows lawns during the summer in his neighborhood. Jeremy has made $800 mowing 35 lawns. He charged either $20 or $25 a lawn. For the 35 lawns mowed, how many times did Jeremy charge $20?

Respuesta :

the answer is 15. I know because I got this one wrong. I hope I helped.
lublana

Given that Jeremy mows two types of lawns during the summer in his neighborhood.

Let number of lawns that are charged at $20 = x

then total earning from x such lawns = 20x


Let number of lawns that are charged at $25 = y

then total earning from y such lawns = 25y


Then his total earning = 20x+25y

Given that he earned $800 so we get equation:

20x+25y=800...(i)


Since total number of lawns are 35 so we get:

x+y=35

or x=35-y...(ii)


Plug (ii) into (i)

20(35-y)+25y=800

700-20y+25y=800

700+5y=800

5y=800-700

5y=100

y=100/5

y=20


Now plug value of y=20 into (ii)

x=35-20=15


Hence Jeremy charged 15 lawns at $20.


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