Question

I think of a decimal number. After I have subtracted 2.9 from it, then multiplied by 3 and then added 0.15, I get 10.5. What is the decimal number?

• A. 4.5
• B. 15.66
• C. 20.1
• D. 6.35

Answer 1

The correct option is D 6.35

Let the decimal number be x.

$3(x-2.9)+0.15=10.5$

$3x-8.7+0.15=10.5$

$3x-8.7=10.35$

$3x=19.05$

$x=6.35$.