Engineering Board Exam Reviewer · Number & Digit Problems · medium
A two-digit number is 4 more than 3 times the sum of its digits. When its digits are reversed, the number increases by 27. Find the number.
- 52
- 36
- 47
- 25
Answer
D. 25
Solution
Let the number be 10t+u. Then 10t+u=3(t+u)+4 7t-2u=4. Reversing adds 27: 9(u-t)=27 u=t+3. Substituting: 7t-2t-6=4 t=2, u=5. The number is 25.
More Number & Digit Problems questions
- The product of two consecutive positive odd integers is 143. Find the larger integer.
- The sum of two numbers is 40 and their difference is 12. Find the larger number.
- The sum of three consecutive even integers is 78. What is the largest integer?
- The sum of two numbers is 5 and the product of these two numbers' reciprocals is 7. Find the sum of their reciprocals.
- In a two-digit number, the unit's digit is 3 greater than the ten's digit. Find the number if it is four times as large as the sum of its…
- The sum of the digits of a 3-digit number is 17. The hundred's digit is twice the unit's digit. If 396 will be subtracted from the number…
- In a box there are 25 coins consisting of quarters, nickels and dimes with a total amount of 2.75 USD. If the nickels were dimes, the…
- The denominator of a certain fraction is three more than twice the numerator. If 7 is added to both terms of the fraction, the resulting…
- The sum of the digits of a two-digit number is 11. If the digits are reversed, the resulting number is seven more than twice the original…
- Joey was told to carry 20 cans to a store. Joey can carry only 3 cans at a time. How many trips would Joey have to make?