A word problem.?

Question

Buck invested $1992. He invested some at 9.34% and the rest at 8.57%. The interest earned at the end of the year was $181.59. How much did he invest at 9.34%?

Answer 1

x + y = 1992 (the total amount of he invested)

Also,

x(.0934) + y(.0857) = 181.59 (total amount of interest)

Now, let's substitute in:

(1992 - y) (.0934) + .0857y = 181.59

(186.05 - .0934y) + .0857 y = 181.59

186.05 - .0077y = 181.59

-.0077y = -4.46

y = 579.22

Therefore,

x + y = 1992

x = 1992 - 579.22

x = 1412.78

Check:

1412.78 (.0934) = $131.95
579.22 (.0857) = $49.63

$131.95 + $49.63

= $181.58

(Probably off that penny due to rounding somewhere.)

Good luck!

Mysstere