This should help i guess but if is still not clear i might just fail

Question 19:

To get the answer we just have to round up the number then multiply...

9.8% = 10%

5.5% = 5%

19.8 = 20%

(Use the rounding rule, but in 2014 the 20 tons actually increase by 10%, this is where me multiply)

Our equation should look like 20(1.10) so far...

In 2015, we would need to increase the quantity by 5%, which means we would multiply that quantity by 1.05.

D) 20(1.1)(1.05)

Question 27:

First, let's find out the discount during the sale, we know there was a 40% discount...

When we use percentages we know it's out of 100...so...

450 * (100% - 40%)

450 * (60%)

450 * (0.6

= 270

After the sale it increases by 40%...

100% + 40% = 140%

140% = 1.4

270 x 1.4

= 378

C) 378

I hope this helps, hopefully my explanation made sense...