Hello!
First you to do 65 * 0.20
0.20 is 20% as a decimal
65 * 0.20 = 13
$13 is how much John saves.
To find out how much the skateboard cost you subtract how much he saved by the cost of the skateboard
65 - 13 = 52
The skateboard cost $52
Hope this helps!
Answer:
3156
Step-by-step explanation:
- <em>Used formula:</em>
- <em>(1² + 2² + 3² + ... + n²) =1/6*n(n + 1)(2n + 1)</em>
--------
- 10²+12²+14²+......+26² =
- (2*5)²+(2*6)² + (2*7)² + ... + (2*13)² =
- 4*(5²+6²+7²+...+13²) =
- 4*(1²+2²+...+13² - (1²+2²+3²+4²)) =
- 4*(1/6*13(13+1)(2*13+1) - (1+4+9+16)) =
- 4*(1/6*13*14*27- 30) =
- 4*(819 - 30) =
- 4*789 =
- 3156
Using it's concept, it is found that there is a 0.001 = 0.1% probability that he will forget to brush his teeth three days in a row.
<h3>What is a probability?</h3>
A probability is given by the <u>number of desired outcomes divided by the number of total outcomes</u>.
In this problem, for each day, there is a 0.1 probability that he forgers to brush his teeth, and days are independent, hence for 3 consecutive days the probability is given by:
p = (0.1)³ = 0.001.
More can be learned about probabilities at brainly.com/question/14398287
#SPJ1
Star at -20 and go back by -5 on the number line
