Thread: Simultaneous Linear Equations help.

Q1
An investor received $1400 per annun from a sum of money, with part of it invested at 10% and the remainder at 7% interest. This investor found that if she interchanged the amounts she had invested she could increase her return by $90 per annun. Calculate the total amount invested.


Q2
A shopkeeper sold his entire stock of shirts and ties in a sale for $10 000. The hirts were priced at 3 for $100 and the ties $20 each. If he had sold only half the shirts and two-thirds of the ties he would have $6000. How many of each did he sell?

Any help would be appreciated. I would also like to know how to figure these out step by steps.

Thank you for reading.

Question 1
Let x be the amount of money invested with the 10% interest.
Equation would be


Invested in 10% = $575, invested in 7% - $825

Question 2
Let x be the amount of shirts the shopkeeper owns
Let y be the amount of ties the shopkeeper owns
Hence,
- eqn 1

- eqn 2
eqn 2 - eqn 1 =

You got the answer for Q2, but not Q1. Thanks anyways.