Final answer:
The ratio to describe the money in Zaniyah's piggy bank to the money in her brother's piggy bank is 7:4.
Step-by-step explanation:
Zaniyah saves $4 for every $7 her brother saves. To find the ratio, we can set up a proportion using the amounts saved by each. Let x be the amount Zaniyah saves and y be the amount her brother saves. We can write the proportion as:
x/4 = y/7
To simplify, we cross multiply:
7x = 4y
Now we can find a ratio by dividing both sides of the equation by y:
7x/y = 4y/y
7x/y = 4
The ratio to describe the money in Zaniyah's piggy bank to the money in her brother's piggy bank is 7:4.