Question

rachel and rosa each invested the same amount of money in bonds. Rachel got an 8% return on her money and rosa got a 9% return. If rosa's annual interest was $500 more than rachel's, how much did each invest? Do i need a chart for this problem?

Answer 1

Yes, you can use a chart.

Interest = Principle x rate x time

Time is 1 year

Interest = Principle x rate x time

They invested the same amount.

Rachel: x = .08 P (x = Rachel's interest)

Rosa: y = .09 p
( y = Rosa's interest.)
y = 500 + x

so, you have x = .08P and
500 + x = .09 P

x/.08 = p

(500 + x)/.09 = p

since the principles are the same then

x/.08 = (500+x)/.09

This will give you the interest, then you can substitute into I = Prt to find the Principle.