There are 70 fish in the tank. Half of the fish have orange spots and 1/5 of the remaining fish have orange and black spots. How many fish have orange and black spots?

7 orange and black fish

Step-by-step explanation:

a fifth of the remaining fish is 7 because you are doing 35*1/5. 35 is the remaining number of fish because already half of the other fish is 35 and they are orange

b) 1/3 * 1/5

step-by-step explanation:

each smallest part is 1/15 since the written one is 1/5 and it's divided by 3 equal parts. (1/5 )/3 = 1/15 = 1/3 * 1/5