I need help on that to. We have a test tomorrow and I can't figure it out and I need help:(
Answer:
13
Step-by-step explanation:
6-(-7)=13
Answer:
n+2
Step-by-step explanation:
This is a Typical Question on Arithmetic Progression with initial term as 2n+1
The next number in this particular series will be 2n+1+2 which is 2n+3 and so on. Thus a common difference of 2 exists.
The nth term of an Arithmetic Progression AP, bn is represented below where b1 is the first term
bn=b1 +(n-1)d where d is the common difference
For this particular series, the 4th term b4 is
b4= 2n+1+(4-1)2 0r b4 =2n+1+6=2n+7
sum of series is represented by equation: n(b1 +b4)/2 where b1 and b4 are 1st and 4th term respectively
Thus Sum required =4(2n+1+2n+7)/2=4(4n+8)/2=8n+16 0r n+2
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
