Answer:
The answer could be easier if you make a ratio and actual graph
Step-by-step explanation:
John bought 18 erasers.
Explanation: He has $6.00
He spends $3.12 on notebooks
Then you do $6.00 - $3.12 and you get $2.88
If it’s ¢16 per eraser and he has no money left over after buying erasers than you would divide $2.88 by $0.16 which turns into 288 divided by 16 which comes out to 18.
Therefor John bought 18 erasers.
27.034%
Let's define the function P(x) for the probability of getting a parking space exactly x times over a 9 month period. it would be:
P(x) = (0.3^x)(0.7^(9-x))*9!/(x!(9-x)!)
Let me explain the above. The raising of (0.3^x)(0.7^(9-x)) is the probability of getting exactly x successes and 9-x failures. Then we shuffle them in the 9! possible arrangements. But since we can't tell the differences between successes, we divide by the x! different ways of arranging the successes. And since we can't distinguish between the different failures, we divide by the (9-x)! different ways of arranging those failures as well. So P(4) = 0.171532242 meaning that there's a 17.153% chance of getting a parking space exactly 4 times.
Now all we need to do is calculate the sum of P(x) for x ranging from 4 to 9.
So
P(4) = 0.171532242
P(5) = 0.073513818
P(6) = 0.021003948
P(7) = 0.003857868
P(8) = 0.000413343
P(9) = 0.000019683
And
0.171532242 + 0.073513818 + 0.021003948 + 0.003857868 + 0.000413343
+ 0.000019683 = 0.270340902
So the probability of getting a parking space at least four out of the nine months is 27.034%
2(20+60+48)=2(128)= 256 square inches
Hope it helps
