12-7=5 or 12-5=7, it’s all in the fact families//basic addition
Answer:
22,828
Step-by-step explanation:
(<em>a</em> ² + <em>b</em> ²) / (<em>ab</em>) = <em>a</em>/<em>b</em> + <em>b</em>/<em>a</em> = (√3 - √2) + 1/(√3 - √2)
Rationalize the denominator of the second term:
1/(√3 - √2) • (√3 + √2)/(√3+√2) = (√3 + √2)/((√3)² - (√2)²) = √3 + √2
So we have
(<em>a</em> ² + <em>b</em> ²) / (<em>ab</em>) = (√3 - √2) + (√3 + √2) = 2√3
12/5 = 2.4 min
2.4 minutes - 2 minutes
= 0.4 minutes
60/10=6
6*4=24
It takes John 24 seconds to assemble a watch.
The expected value of the first game is -$0.50 and of the second game is -$0.52.
There are 10³ possible numbers for the lottery, and only 1 of them will match in the correct order; this gives a probability of 1/1000. To find the expected value, we multiply this by the winnings (499 after the $1 cost); we also multiply the probability of losing (999/1000) by the amount lost (-1):
1/1000(499)+999/1000(-1)
499/1000 - 999/1000 = -500/1000 = -0.50
For the second game, since the number is "boxed", there are 3! ways to get the correct digits; this gives a probability of 6/1000. Multiply this by the winnings, 79 (after the $1 cost); multiply the probability of losing (994/1000) by the loss (-1):
6/1000(79) + 994/1000(-1) = 474/1000 - 994/1000 = -520/1000= -0.52
