In the fish tank 6/7 of the fish have a red stripe on them. is 18 of the fish have red stripes how many total fish are in the tank?

21

Step-by-step explanation: We know that 6/7 of the fish in the tank have red stripe on them, and the exact number is 18.

This means that, of a number of total fish, X, when we multiply it by 6/7, we obtain 18 as result:

6/7*X = 18

X = 18*7/6 = 21

So we have a total of 21 fish in the tank, where 18 red fish have a red stripe, and the other 3 are different.

7 weeks

step-by-step explanation:

convert each fraction to the least common multiple of 20, so 3/4 = 15/20 & 1/10 = 2/20, then divide 15 by 2 and you get a little over 7, so the food will last 7 weeks.

78.59 is the mean

step-by-step explanation: