Answer:
(7,-1)because it is problem of vector lesson so that we have to use formula of vector
(7,0), (-7,0), (0,7), (0,-7)
X = number of singles matches
y = number of doubles mnathes
so we have the equation x + y = 13.......(1)
also
2x + 4y = 38 ...........(2)
(1) and (2) are the required equations
b) Find how many maches are in progress by solivng the above equations:-
x + y = 13 multiply this by -2:-
-2x - 2y = -26
2x + 4y = 38 Adding to removes the terms in x:-
2y = 12
y = 6
so x = 13-6 = 7
So the answer is 6 double matches and 7 singles are in progress.
Whisper-20dB
Quiet Residence-30dB
Soft stereo in Residence-40dB
Average Speech-60dB
Cafeteria-80dB
Pneumatic Jackhammer-90dB
Loud crowd noise-100dB
Accelerating Bike-100dB
Rock concert-120dB
Jet Engine (75 ft away)-140dB
(1)Mode=100dB (since 100 is occurring the maximum no. of times, i.e. it has the highest frequency of 2)
(2)Mean=sum of observations/Total number of observations
=(20+30+40+60+80+90+100+100+120+140)/10
=770/10=10dB
(3)Median= 1/2[{n/2}th observation + {(n/2)+1}th observation], where, n=total no. of observations
So, 1/2[{10/2}th observation + {(10/2)+1}th observation]
=1/2[5th observation+6th observation]
=1/2[80+90] [Because:5th observation=80dB and 6th=90dB]
=1/2(170)
=85
Therefore, median=85dB
