Question

solve. if the problem asks for a ratio, give it in simplified form.
7 lauren wants to both spend and save the money she earns. for every $7 she puts in her purse, she puts $3 in savings.
a. if lauren puts $70 in her purse, how much money would she put
b. if lauren earns $70 total, how much will she put into savings?
c. what is the ratio of money saved to total money earned?

Explanation:

Part a

Step1: Find the ratio of savings to purse

The ratio of purse money to savings is $7:$3, so the ratio of savings to purse is $3:$7.

Step2: Calculate savings for $70 purse

Let $x$ be savings. $\frac{3}{7}=\frac{x}{70}$, cross - multiply: $7x = 3\times70$, $7x=210$, $x = 30$.

Step1: Find total parts of money

The ratio of purse to savings is $7:3$, so total parts $=7 + 3=10$.

Step2: Calculate savings for $70 total

Savings is $\frac{3}{10}$ of total. So savings $=\frac{3}{10}\times70 = 21$.

Step1: Identify amounts

Savings per ratio is $3$, total per ratio is $7 + 3 = 10$.

Step2: Find the ratio

Ratio of savings to total is $3:10$.

Answer:

$30

Part b