15 because simple division 30 divided by 2 is 15 only 15 can happen
Answer:
36 erasers
Step-by-step explanation:
Let number of erasers be e
let number of rulers be r
We can write:
e + r = 70
and
After giving away, he has
Erasers: 2/3e
Rulers: r - 10
These two are equal, so we can write and solve:
2/3e = r - 10
2/3e + 10 = r
Putting this in initial equation, we have:
e + (2/3e + 10) = 70
5/3e + 10 = 70
5/3 e = 60
e = 36
And rulers is:
r = 2/3(36) + 10 = 34
Hence, he had 36 erasers in the beginning
400 : 1kg
400 : 1000
1 : 2.5
n = 2.5
The 68-95-99.7 rule tells us 68% of the probability is between -1 standard deviation and +1 standard deviation from the mean. So we expect 75% corresponds to slightly more than 1 standard deviation.
Usually the unit normal tables don't report the area between -σ and σ but instead a cumulative probability, the area between -∞ and σ. 75% corresponds to 37.5% in each half so a cumulative probability of 50%+37.5%=87.5%. We look that up in the normal table and get σ=1.15.
So we expect 75% of normally distributed data to fall within μ-1.15σ and μ+1.15σ
That's 288.6 - 1.15(21.2) to 288.6 + 1.15(21.2)
Answer: 264.22 to 312.98
Tan(60)=Opposite or L /20cm
*20. *20
Tan(60)*20=L
34.64101615=L
34.64 (to the nearest hundredth of a meter or cm)
