Question

The water level of a lake fell by 1 1/4 in. during a 1 1/2 week long drought what is the average rate at which the water level changed every week

Answer 1

Answer:

$\frac{5}{6}$  inches per week

Step-by-step explanation:

This is a very simple ratio problem. Basically,

If $1\frac{1}{4}$ inches in  $1\frac{1}{2}$ week, then HOW MANY INCHES (let it be x) in 1 week???

We set up two ratios and cross multiply and solve for x:

$\frac{1\frac{1}{4}}{1\frac{1}{2}}=\frac{x}{1}\\1\frac{1}{4}*1=1\frac{1}{2}*x\\1\frac{1}{4}=1\frac{1}{2}x\\x=\frac{1\frac{1}{4}}{1\frac{1}{2}}\\x=\frac{\frac{5}{4}}{\frac{3}{2}}\\x=\frac{5}{4}*\frac{2}{3}\\x=\frac{5}{6}$

So average rate at which the water level changed every week is 5/6 inches per week.