What would be cost of toaster in this problem? A man sold a toaster at a loss of 8%. Had he bought it at 10% less and sold for $88 more he would have gained 20%. What would be cost of toaster.

Let's say that he bought the toaster at price $B$ and sold it at price $S$. To lose 8%, he must have sold it at only 92% of what he bought it for:

$$S = 0.92 \times B$$

Let $S'$ and $B'$ be the new selling and buying prices. If he were to make a 20% profit then

$$S' = 1.2 \times B'$$.

You said that the new buying price 10% less, so $B'=0.9 \times B$ and you said that he sold it for $88$ more. That means $S' = S + 88$. Putting this into $S'=1.2 \times B'$ gives:

$$S+88 = 1.2 \times 0.9 \times B$$

You need to solve the two equations: $S=0.92B$ and $S+88=1.08B$. Putting the first into the second:

$$S+88 = 1.08B \implies 0.92B + 88 = 1.08B \implies 88 = 0.16B \implies B = 550$$

If $B = 550$ then $S=506$.