Engineering Board Exam Reviewer · Number & Digit Problems · medium
The sum of two numbers is 5 and the product of these two numbers' reciprocals is 7. Find the sum of their reciprocals.
- 7/5
- 5/7
- 2/5
- 3/7
Answer
B. 5/7
Solution
Sum of reciprocals = a+b/ab = 5/7 (since a+b=5 and ab=7).
More Number & Digit Problems questions
- 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?
- For any positive integer k, let f1(k) denote the square of the sum of the digits of k. For n ≥ 2, let fn(k) = f1(fn-1(k)). Find f1988(11).
- The sum of three consecutive even integers is 78. What is the largest integer?