For number 2, like i said in the comments, is 20 hours.
8/12*30
For number three, the answer is 38 Ibs on Mars.
4/10 = x/95
4*95/10= x
X= 380/10 which equals 38.
For 4, the answer is 48 oz of pineapple juice.
3 x 64/4 which equals to 48.
For 5, you will need 6 cups of flour.
Hope this helps & good luck. :)
