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

 It is currently 23 Oct 2019, 11:17

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

What is the value of (s+t) if the equation

Author Message
Manager
Joined: 13 May 2017
Posts: 116
Location: Finland
Concentration: Accounting, Entrepreneurship
GMAT 1: 530 Q42 V22
GMAT 2: 570 Q36 V31
GMAT 3: 600 Q42 V28
GPA: 3.14
WE: Account Management (Entertainment and Sports)
What is the value of (s+t) if the equation  [#permalink]

Show Tags

23 Nov 2018, 04:14
3
00:00

Difficulty:

25% (medium)

Question Stats:

79% (01:25) correct 21% (01:51) wrong based on 29 sessions

HideShow timer Statistics

What is the value of (s+t) if the equation (3$$x^2$$ + tx + s) has 2 and 3 as its roots?

A. 2
B. 3
C. 7
D. 18
E. 33
Senior Manager
Joined: 18 Jun 2018
Posts: 262
Re: What is the value of (s+t) if the equation  [#permalink]

Show Tags

23 Nov 2018, 06:04
2
OA:B

For the Quadratic equation of form $$ax^2+bx+c=0$$

Sum of roots $$= -\frac{b}{a}$$

Product of roots $$= \frac{c}{a}$$

$$-\frac{t}{3}=2+3=5$$

$$t=-15$$

$$\frac{s}{3}=2*3$$

$$s=18$$

$$s+t = 18+(-15) =3$$
Manager
Joined: 26 Feb 2017
Posts: 85
Location: India
GPA: 3.99
Re: What is the value of (s+t) if the equation  [#permalink]

Show Tags

23 Nov 2018, 07:02
2
Putting x=2 in the equation 3x^2+tx+s= 0
3(2)^2 + t(2) + s = 0
12 +2t+s = 0
2t + s = -12........eqn 1

Now putting x = 3 in the equation, we get:
27 + 3t + s = 0
3t + s = -27...... eqn 2

Solving eqn 1 & 2, we get:
t = -15
s = 18

Therefore, t + s = -15 + 18 = 3

Posted from my mobile device
Re: What is the value of (s+t) if the equation   [#permalink] 23 Nov 2018, 07:02
Display posts from previous: Sort by