To add integers there are few rules. if your adding a negative and a negative, the answer is always negative
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
Answer:
Y = -2, X = 4
Step-by-step explanation:
When you first use the elimination method, you would multiply 2x-y = 10 by -2 so that you could get the 4x to be eliminated.
4x-3y = 22
(2x-y = 10)-2 = -4x + 2y = -20
When you add those 2 together you are left with -y = 2, which you divide by negative to get y = -2. Then you substitute -2 for y to solve for x. I substituted the bottom equation
2x - (-2) = 10
2x +2 = 10
2x = 8
Divide both sides by 2 to get x = 4.