Kaya devoted 2/5 of her study time to mathematics, 3/20 of her time to social studies, 1/3 of her time to chemistry and the remaining 42 minutes to English. How much time she spend studying social studies?

54 minutes

Step-by-step explanation:

The sum of fractions is ...

2/5 + 3/20 + 1/3 = 11/20 + 1/3 = (3·11 + 20·1) / (20·3) = 53/60

Then the 42 minutes devoted to English represents 1 - 53/60 = 7/60 of her study time.

Kaya's social studies time is 3/20 = 9/60 of her total, so the ratio of SS to Eng is ...

SS : Eng = (9/60) : (7/60) = 9 : 7

When we multiply the numbers in this ratio by 6, we find ...

SS : Eng = 54 : 42

Kaya spent 54 minutes studying social studies.