For this case we have to:
n: Represents the weight of Mary in Kg.
If your sister weighs 15 kg less we have:

Where "y" represents the weight of his sister in kg.
To find how many times Mary is heavier than her sister, we must divide Mary's weight by her sister's weight.
We have then:

Answer:
Mary is
times heavier than her sister.
Answer:
14.16
Step-by-step explanation:
we first calculate the total amount of money paid, which is 35.40 plus 20%, we use this calculation:
35.40×1.20 = 42.48
now, this amount is split to 3 people, so:
42.48/3 = 14.16
and that is our answer
Answer:
38.4
Step-by-step explanation:
it took 48 minutes and the app miss estimated by 9.6, which is 20% of 48. So subtract 9.6 from 48 and you will get 38.4
Answer:
a) night, from cool land to sea
b) day, from cool sea to land