How many gallons of water are used to fill 2 fish tanks

Jonathan pays $1.90 per pound for potatoes. he buys 8.3 pounds of potatoes. he determines that he will pay $15.77, before tax, for the potatoes. which best describes the reasonableness of jonathan’s solution? jonathan’s answer is reasonable because there are two decimal places in the factors and two in the product. jonathan’s answer is unreasonable because there are three decimal places in the factors and two in the product. jonathan’s answer is reasonable because is 16, and 16 is close to 15.77. jonathan’s answer is unreasonable because is 8, and 8 is not very close to 15.77.

Can anyone explain to me how to do this? anything will .

An archaeologist in turkey discovers a spear head that contains 53% of its original amount of c-14. find the age of the spear head to the nearest year. (5250 isn’t right)