Algebra
posted by sherry on .
Select the set of equations that represents the following situation: Mike invested $434 for one year.He invested part of it at 9% and the rest at 10%.At the end of the tear he earned $40.16 in interest.How much did Mike invest at each rate of interest.?
a).x+y=434;9x+10y=40.16
b.)0.09+0.10y=$434;x+y=40.16
c.)x=y=434*0.09x+0.10y
0.09*434+0.10=434=40.16

Mike invested:
$X @ 9%.
$Y @ 10%.
Eq1: X + Y = 434.
Eq2: 0.09X + 0.10Y = 40.16.
Multiply BOTH sides of Eq2 by 100:
Eq2: 9X + 10Y = 4016.
NOTE: Under choice "a", They forgot to
multiply the rt side by 100. Thererfore,if they change 40.16 to 4016; "a" would be the correct choice.