7x-5<13x-3
Minus 7x
-5<6x-3
then add 3
-2<6x
Then divide -2 by 6 and 6x by 6
-1/3>x
I think thats right
9. One is 6 over par, the other is three under, so subtract first-second = 6-(-3) = 9
Given that mean=3750 hours and standard deviation is 300:
Then:
<span>a. The probability that a lamp will last for more than 4,000 hours?
P(x>4000)=1-P(x<4000)
but
P(x<4000)=P(z<Z)
where:
z=(x-</span>μ)/σ
z=(4000-3750)/300
z=0.833333
thus
P(x<4000)=P(z<0.8333)=0.7967
thus
P(x>4000)=1-0.7967=0.2033
<span>b.What is the probability that a lamp will last less than 3,000 hours?
P(x<3000)=P(z<Z)
Z=(3000-3750)/300
z=-2.5
thus
P(x<3000)=P(z<-2.5)=0.0062
c. </span><span>.What lifetime should the manufacturer advertise for these lamps in order that only 4% of the lamps will burn out before the advertised lifetime?
the life time will be found as follows:
let the value be x
the value of z corresponding to 0.04 is z=-2.65
thus
using the formula for z-score:
-2.65=(x-3750)/300
solving for x we get:
-750=x-3750
x=-750+3750
x=3000</span>
Answer:
12 pull
As 48 seconds + 20 seconds push = 68 seconds
Step-by-step explanation:
Because she did 10 push = 20 seconds = 2 seconds each
12 pull = 48 seconds = 4 seconds each
= 68 seconds combined.
Workings;
18 seconds found for the first set
We then find a divider of 68 and know that
6 x 3 = 18 seconds push
12 x 3 =36 seconds pull T= 54
14 left over = 1 x 12 seconds pull
+ 2 seconds push
= 10 push = 20 seconds combined.
= 12 pull = 48 seconds combined.
Answer:
Step-by-step explanation:
The ratio of new length 7 to the initial length 19 is 2.7
Therefore new width will be 2.7×4 which will be 10.9 or about 11 inches
