-1. My grandson is about as many days as my son is weeks, and my grandson is as many months as I am in years. My grandson, my son and I together are 100 years. Can you tell me my age in years?

-2. It was vacation time, and so I decided to visit my cousin's home. What a grand time we had! In the mornings, we both would go for a jog. The evenings were spent on the tennis court. Tiring as these activities were, we could manage only one per day, i.e., either we went for a jog or played tennis each day. There were days when we felt lazy and stayed home all day long.

Now, there were 14 mornings when we did nothing, 11 evenings when we stayed at home, and a total of 13 days when we jogged or played tennis. For how many days did I stay at my cousin's place?

-3. Fill the empty boxes with fractions so that each row, each column and each of the long diagonals totals 1.

3.

1: I think it works this way; not sure due to word "about".

a = grandfather/mother
b = son
c = grandson

>My grandson is about as many days as my son is weeks,
b = 7c [1] (1 week = 7 days)

>and my grandson is as many months as I am in years.
a = 12c [2] (1 year = 12 months)

>My grandson, my son and I together are 100 years.
a + b + c = 100 ; substitute [1] and [2]:
7c + 12c + c = 100
20c = 100
c = 5

>Can you tell me my age in years?
[2]: a = 12c = 12*5 = 60

Two excellent solves!

Starter hints for #2

SO:
T - 14 + T - 11 = 13 (days jogging or tennis)
2T = 38
T = 19

Got an Extra Strength Tylenol for me???

You crushed it, Denis!