M4maths Previous Puzzles

11 Jul 2013 Problem

The power, in mega watts (MW), produced between midnight and noon in a nuclear power plant is given by P=4h^2-48h+744, where h is the hour of the day. At what times is the power 664 MW.

OPtion

1) 3 A.M and 9 A.M
2) 2 A.M and 10 A.M
3) 2 A.M and 8 A.M
4) 5 A.M and 10 A.M
5) 10 A.M and 11 A.M
6) 4 A.M and 8 A.M
7) 3 A.M and 10 A.M
8) 2 A.M and 9 A.M
9) 6 A.M and 8 A.M
10) None of these

Solution

Solve Equation
4h^2-48h+744=664
h=10,2
The power is 664 MW at 2 A.M and 10 A.M
option 2

Correct Option: 2 Best Solution (26)

Madan kumar   11 years AGO

4h^2 -48h + 744 =664

4h^2 -48h +80=0

h^2 -12h +20=0

(h-2)(h-10)=0

h=2 am , 10 am

Like? Yes (6) | No (2)  

Pradyumna K S   11 years AGO

P=4h^2-48h+744
here power p is 664MW
therefore, 664=4h^2-48+744
4h^2-48+744-664=0
4h^2-48+80=0
h^2-12h+20=0
h^2-10h-2h+20=0
h(h-10) 2(h-10)=0
h=10 h=2
hours h is 10 AM and 2 AM.
i.e option 2)2 A.M and 10 A.M

Like? Yes (5) | No (1)  

Jasmine Khan   11 years AGO

p=664
therefore,
664=4h^2-48h+744
4h^2-48h+80=0
h^2-12h+20=0
(h-2)(h-10)=0
h=2 and h=10

Like? Yes (3) | No   

Jigyasa Kumar   11 years AGO

p= 4h^2-48h+744
the question gives the condition that power = 664
then,
p=664
so the new equation becomes :
664= 4h^2-48h+744
on further solving 4h^2-48h+80=0
so (h-10)(h-20)=0
so h=2,10
ANSWEE : 2,10

Like? Yes (4) | No (2)  

Aarush Singh   11 years AGO

solve 664=4h^2-48h+744
answer = h=2,10

Like? Yes (3) | No (1)  

Adarsha Upadhya   11 years AGO

on solving 4h^2-48h+744=664-------1
4h^2-48h+80=0
h1=2 and h2=10

Like? Yes (3) | No (1)  

pravallika nathi   11 years AGO

h^2-12h+20=0
h=2 and h=10

Like? Yes (1) | No   

Ankit Mundra   11 years AGO

Make a quadratic equation ..
4h^2-48h+744=664

On solving this, we'll get the required result.

Like? Yes (1) | No   

MRINAL   11 years AGO

given,
p=4h^2-48h+744
to calculate out the time when th power is 664mw
put p=664
therefore,
664=4h^2-48h+744
i.e,4h^2-48h+80=0
i.e,h^2-12h+20=0
i.e,[(h-2)(h-10)]=0
either h=10 or h=2
hence option(2)

Like? Yes (1) | No   

RaviTeja   11 years AGO

solve quadratic eqn..u'll get it!

Like? Yes (1) | No   

Thaiyalnayaki   11 years AGO

4h^2-48h+744=664
4h^2-48h+80=0
/ 4,h^2-12h+20=0
solving we get h=2,10

Like? Yes (1) | No   

Devendra Marghade   11 years AGO

P=4h^2-48h+744=664 or
4h^2-48h+80=0
4h^2-40h-8h+80=0
(4h-8)(h-10)=0, h=2,10

Like? Yes (1) | No (1)  

raksha agrawal   11 years AGO

equation i sh2-12h+20, which means h=2and 10

Like? Yes (1) | No (1)  

raghu   11 years AGO

solving the equation
4h^2-48h+744=644
gives h=2,10

Like? Yes (1) | No (1)  

shailesh kumar mishra   11 years AGO

put p=664
then 4h^2-48h+744-664=0 by solving we get h=2,h=10

Like? Yes (1) | No (1)  

anjul meid   11 years AGO

4h^2+48h+744=664=>h^2+12h+20=0=>h=2,10

Like? Yes (1) | No (1)  

Himanshu Kumar Gupta   11 years AGO

Putting p=664 in the given equation we get h=2 and h=10

Like? Yes (1) | No (1)  

sameer singh   11 years AGO

664=4h^2-48h+744
h^2-12h+20=0
h=10 and 2

Like? Yes (1) | No (1)  

Shyoram   11 years AGO

simply solve the equation

Like? Yes (1) | No (1)  

raviteja   11 years AGO

by option verification only 2 and 10 satisifies the eqn to get 664 Mw power

Like? Yes (1) | No (1)  

FRANKLIN VIJAY   11 years AGO

if we substitute 2 and 10 in the equation P=4h^2-48h+744 then we get the power of 664mw.

Answer is 2 am and 10 am

Like? Yes (1) | No (1)  

vinod   11 years AGO

verify options

Like? Yes (1) | No (1)  

Udhaya kumar   11 years AGO

4h^2-48h+744=664
h^2-12h+20=0
By solving this we get 2 and 10....

Like? Yes (1) | No (1)  

Sarankumar Chandrasekaran   11 years AGO

Equation Method

Like? Yes (1) | No (1)  

bandla madhu   11 years AGO

4h^2-48h+80 = 0 solve this u will get h as 2 or 10

Like? Yes (1) | No (1)  

Roopam Jain   11 years AGO

just solve the quadratic equation :
4h^2-48h+744=664
Gives h = 2,10

Like? Yes (1) | No (1)