Question 1156145
1.)
Assign variables.
Let the 3 consecutive numbers be:  a, b, c.

a < b < c

2a + 3b + c = 53
also   consecutive means   b = a + 1,  c = a + 2

2a + 3*(a + 1) + (a + 2) = 53
2a + 3a + 3 + a + 2 = 53
6a + 5 = 53
6a = 48
a = 8,
The consecutive numbers are 8, 9, and 10

2.)   M = 6 + S ,    2M = 4S - 8

or M = 2S - 4,     2S - 4 = 6 + S,     S = 6 + 4,   S = 10
Then Mark is 6 + 10 = 16 years old
Stephanie is 10 years old.
Mark is 16 years old

3.)