A brand of cereal had 1.2 milligrams (mg) of iron per serving. Then they changed their recipe so they had 1.8 mg of iron per serving. What was the percent increase in iron?

Can someone check if i did this correct. it’s number 4 if you’re wondering.

The volume of gas a balloon can hold varies directly as the cube of its radius. imagine a balloon with a radius of 3 inches can hold 81 cubic inches of gas. how many cubic inches of gas must be released to reduce the radius down to 2 inches?

In a certain city, the hourly wage of workers on temporary employment contracts is normally distributed. the mean is $15 and the standard deviation is $3. what percentage of temporary workers earn less than $12 per hour? a. 6% b. 16% c. 26% d. 36%