Question

Add 15 to a number, then multiply the result by 3. the answer is the Same as subtracting 4 from the number and multiplying the result by 5. find the number.

Answer 1

Step-by-step explanation:

15x3=45

49-4=45

45x5=225

Answer 2

Answer:

Let the number be x.

Given, if we add 15 to x and multiple the result by 3 , the answer will be equal to 4 subtracted from x and multiplying the result by 5. The following equation is formed:

• (15 + x) × 3 = (x - 4) × 5

We know that multiplication is commutative, therefore, let's simplify the equation:

• 3(15 + x) = 5(x - 4)

Now, using the transposition method, we solve the equation:-

• 45 + 3x = 5x - 20 (using distributive property over addition and subtraction)
• 3x - 5x = -20 - 45 (transposing 45 to the RHS and 5x to the LHS)
• -2x = -65
• x = -65/-2 (transposing -2 to the RHS)
• x = 65/2

Verification:

Putting x = 65/2,

• 3(15 + 65/2) = 5(65/2 - 4)
• 45 + 195/2 = 325/2 - 20
• 90/2 + 195/2 = 325/2 - 40/2 (converting the numerals into equivalent fractions)
• 90 + 195/2 = 325 - 40/2
• 285/2 = 285/2
• LHS = RHS

Hence, verified.