GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 24 Jun 2018, 04:03

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Two numbers have a sum of 10 and a product of 20. What is the sum of t

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 46305
Two numbers have a sum of 10 and a product of 20. What is the sum of t [#permalink]

### Show Tags

13 Sep 2017, 01:45
00:00

Difficulty:

35% (medium)

Question Stats:

79% (01:19) correct 21% (02:36) wrong based on 38 sessions

### HideShow timer Statistics

Two numbers have a sum of 10 and a product of 20. What is the sum of the reciprocals of the two numbers?

A. 1/10
B. 1/8
C. 1/4
D. 1/2
E. 2

_________________
Senior Manager
Joined: 02 Jul 2017
Posts: 294
GMAT 1: 730 Q50 V38
Re: Two numbers have a sum of 10 and a product of 20. What is the sum of t [#permalink]

### Show Tags

13 Sep 2017, 03:18
Let 2 numbers be a and b.
Given: a+b =10 and a*b =20

Find : $$\frac{1}{a} + \frac{1}{b}$$

as a+b=10 and ab =20

=>$$\frac{a+b}{ab} =\frac{10}{20}$$

=>$$\frac{a}{ab} + \frac{b}{ab} =\frac{1}{2}$$

=>$$\frac{1}{b} +\frac{1}{a} = \frac{1}{2}$$ = Answer

Intern
Joined: 13 Sep 2017
Posts: 1
Re: Two numbers have a sum of 10 and a product of 20. What is the sum of t [#permalink]

### Show Tags

13 Sep 2017, 03:19
The two numbers are 5+sqroot(5) and 5-sqroot(5) solving the reciprocals of the two numbers the answer is 1/2.

Sent from my iPhone using GMAT Club Forum mobile app
SC Moderator
Joined: 22 May 2016
Posts: 1765
Two numbers have a sum of 10 and a product of 20. What is the sum of t [#permalink]

### Show Tags

13 Sep 2017, 03:22
1
1
Bunuel wrote:
Two numbers have a sum of 10 and a product of 20. What is the sum of the reciprocals of the two numbers?

A. 1/10
B. 1/8
C. 1/4
D. 1/2
E. 2

x + y = 10
xy = 20

What is the sum of the reciprocals of the two numbers?

$$\frac{1}{x}$$ + $$\frac{1}{y}$$ = $$\frac{(x + y)}{xy}$$

Substituting values from above for (x + y) and (xy):

$$\frac{10}{20}$$ = $$\frac{1}{2}$$

_________________

In the depths of winter, I finally learned
that within me there lay an invincible summer.

Two numbers have a sum of 10 and a product of 20. What is the sum of t   [#permalink] 13 Sep 2017, 03:22
Display posts from previous: Sort by