Question

A is now 34 years old, and B is 4 years old. In how many years will A be twice as old as B?

Answer 1

Hint: In this question, we are given the present ages of two people A and B and we have to find the number of years after which A will be twice as old as B, for that we let the number of years to be represented by “x”. First, we will add x with 34 and then with 4, then we will put the twice of 4 plus x equal to 34 plus x. Thus we can find the value of x by solving the obtained equation

Complete step-by-step answer:
The present ages of A and B are 34 and 4 respectively. Ages of A and B after “x” years are 34+x and 4+x respectively. The value of x for which the age of A is twice the age of 4 is found as follows –
$
x+34 = 2(x+4)\\
x+34 = 2x+8\\
34-8 = 2x-x\\
26=x\;
$
Hence, A is twice as old as B after 26 years.
So, the correct answer is “ 26 years”.

Note: When we represent some unknown quantities by alphabets and get an equation containing alphabets and numerical values, the equation is called an algebraic expression. An algebraic expression is used to convert a statement into a mathematical expression as in this question. To get the answer, we express one side of the equation in terms of “x“ and the other side as numerical values. And then apply the arithmetic operations to find the value of the “x”.