a shopkeeper sold a certain number ( a two-digit number)of toys all priced at a certain value (also a two-digit number when expr
essed in rupees). by mistake he reversed the digits of both , the number of items sold and the price of each item. in doing so he found that his stock left at the end of the day showed 72 items more than what it actually was. what could be the actual number of toys?
The answer is 91 toys sold, make
the number ab where a is the 10th digit and b is the first digit. The
value is 10a + b that can expressed as 10 (3) + 4 = 34
Let the price of each item: xy
10x + y
He accidentally reversed the
digits to: 10b + a toys sold at 10y + x rupees per toy. To get use the formula,
he sold 10a + b toys but thought he sold 10b + a toys. The number of toys that
he thought he left over was 72 items more than the actual amount of toys left
over. So he sold 72 more toys than he thought:
10a + b =10b + a +72
9a = 9b + 72
a = b + 8
The only numbers that could work
are a = 9 and b = 1 since a and b each have to be 1 digit numbers. He reversed
the digits and thought he sold 19 toys. So the actual number of toys sold was
10a + b = 10 (9) + 1 = 91 toys sold. By checking, he sold 91 – 19 = 72 toys
more than the amount that he though the sold. As a result, the number of toys
he thought he left over was 72 more than the actual amount left over as was
stated in the question.
