1) my brother is 5 years older than me. my sister is 3 years younger than me. how old was i when my brother was k years old? how old will my sister be when i am n years old? 2)the sum of lisa's age and myra's age is 19. in 10 years, lisa will be 5 years older than myra. how old is each girl now?

Answer :

(1) The age of mine was, and The age of sister was,

(2) The Lisa and Myra is 12 and 7 years old girls.

Step-by-step explanation :

Part 1 :

My brother is 5 years older than me.

Let the age of mine be, x

Given : The age of brother is, k years

The equation will be:

So,

The age of mine was,

My sister is 3 years younger than me.

Let the age of sister be, x

Given : The age of mine is, n years

The equation will be:

So,

The age of sister was,

Part 2 :

Let the age of Lisa be, x and the age of Myra be, y

The sum of Lisa's age and Myra's age is 19. That equation will be:

     ..........(1)

In 10 years, Lisa will be 5 years older than Myra. That equation will be:

     ..........(2)

      ............(3)

Using the substitution method and put the equation 3 in equation 1, we get:

Now put the value of y in equation 3, we get the value of x.

Thus, the Lisa and Myra is 12 and 7 years old girls.

step-by-step explanation: