Question

The sum of 3 numbers is 135. The 2nd number is twice the 1st. The 3rd number is 1/2 of the sum of the first two numbers. Find the first number.

Answer 1

Answer:

30

Step-by-step explanation:

Let the first number be $x$.

∴second number = $2x$

Now, third number =$\frac{1}{2}(x+2x) = \frac{3x}{2}$

Since the sum of the three numbers is given as 135,

∴$x+2x+\frac{3x}{2} =135$

⇒$\frac{9x}{2} = 135$

⇒$x=30$

Hence, the first number is 30.

Answer 2

Answer:

Let the first no. be x.

Second number = 2x

Third number = 1/2 × 3x = 3x/2

x+2x+3x/2 = 135

2x+4x+3x/2=135

9x/2 = 135

9x = 135×2

9x = 270

x = 270/9 = 30