Question

21. You and your sister have been saving and decide to buy a PlayStation 5 together. You need $500 to buy the PlayStation. Together you have $850 saved up. Since you have more money, you contribute 50% of your savings and your sister contributes 75% of hers toward the $500 cost. How much do each of you have saved individually?

Answer 1

I have $550; my sister has $300.

Explanation:

Let the amount I have be x.

Let the amount my sister has be y.

We have a total of $850, so

x + y = 850

50% of my amount plus 75% of my sister's amount equals $500.

0.5x + 0.75y = 500

We have a system of two equations:

x + y = 850

0.5x + 0.75y = 500

Multiply the second equation by 2 and subtract the first equation from it.

0.5y = 150

y = 300

x + y = 850

x + 300 = 850

x = 550

Answer: I have $550; my sister has $300.