Question

Kris and Pat were born on the exact same day but not in the same year their ages are shown in the table When Pat was 30 how old was Chris

Answer 1

A ) 18 years old

B) 19 years old

C) 27 years old

add three to kris' age to find Pat's age

Explanation

Step 1

when Kris was 15 .how old was pat

find the rule

a) check if the difference between the ages is constant

$\begin{gathered} \text{Pat's age - Kris' Age=} \\ 7-4=3 \\ 10-7=3 \\ 15-12=3 \\ y_4\text{-}15= \\ 22-x_5= \\ 26-23=3 \end{gathered}$

it means Pat is 3 years older than Kriss

then

when Kris was .how old was pat

$\begin{gathered} y_4\text{-}15=3 \\ y_4-15=3 \\ \text{add 15 in both sides} \\ y_4-15+15=3+15 \\ y_4=18 \end{gathered}$

Step 2

when Pat was 22, How old was Kris

the difference between the ages is the same, 3

so

$\begin{gathered} 22-x_1=3 \\ \text{subtract 22 in both sides} \\ 22-x_5-22=3-22 \\ -x_5=-19 \\ x_5=19 \end{gathered}$

Step 3

when Pat was 30, How old was kris

replace

$\begin{gathered} \text{Pat's age -Kris' age=3} \\ 30-\text{Kri's age=3} \\ \text{subtract 30 in both sides} \\ 30-\text{Kri's age-30=3-}30 \\ -\text{Kris'age =-27} \\ \text{Kris'age }=27 \end{gathered}$

Step 4

wich choice best represents the rule

as we saw before,

add three to kris' age to find Pat's age

$\text{Kris' age+3}=\text{Pat's age}$