Itook a picture of my math questions, take a look.

To solve these you need to set up equal proportions. this means make two ratios that correspond with each other.
420 / 70 = x / 3      Divide
           6 = x / 3      Multiply
         18 = x   
              B

15.
     12 / 8 =  x / 60
         1.5 = x / 60
          90 = x
               C

16.
       3 / 6 = x / 5
           .5 = x / 5
         2.5 = x
               B

Q14: do 70 pages over 3 minutes then do 420over x then cross multiply and then you get 70x=1260 .Then you divide 70 on both sides and end up with 18 minutes.

Q15: take 60 loaves over 8 minutes then put x over 12 minutes. And cross multiply! You end up with 8x=720 then you divide 8 on both sides and your answer is 90 loaves.

Q16: take 6oz over 5 cups then take 3 oz over x and cross multiply. You end up with 6x=15 divide 6 on both sides you end up with 2 1/2 cups! Hope I helped you

Whose mistake? can you give more details to what the question is asking?