a) 220

b) 235

c) 255

d) 265

correct answer is: c) 255

Explanation

The sum is KaTeX parse error: KaTeX doesn't work in quirks mode.
And added number is KaTeX parse error: KaTeX doesn't work in quirks mode.
Let, the number be KaTeX parse error: KaTeX doesn't work in quirks mode.
According to the question,
KaTeX parse error: KaTeX doesn't work in quirks mode.
KaTeX parse error: KaTeX doesn't work in quirks mode.
KaTeX parse error: KaTeX doesn't work in quirks mode.
KaTeX parse error: KaTeX doesn't work in quirks mode.
KaTeX parse error: KaTeX doesn't work in quirks mode.
KaTeX parse error: KaTeX doesn't work in quirks mode.
KaTeX parse error: KaTeX doesn't work in quirks mode. is the number which is multiplied by KaTeX parse error: KaTeX doesn't work in quirks mode. and KaTeX parse error: KaTeX doesn't work in quirks mode. is added to it give the sum KaTeX parse error: KaTeX doesn't work in quirks mode.
Ans: The required number is KaTeX parse error: KaTeX doesn't work in quirks mode.

This particular math question can also be formulated in the following manner: