The probabilities that a man and his wife live for 80 years are $\tfrac{2}{3}$and $\tfrac{3}{5}$respectively. Find the probability that at least one of them will live up to 80 years

The probability that a student passes a physics test$\frac{2}{3}$. If he takes three physics test, what is the probability that he passes two of the tests?

In how many ways can the letters of the word TOTALITY be arranged?

Evaluate $^{n+1}{{C}_{n-2}}$ if n = 15

46 Find the standard deviation of 2, 3, 8, 10 and 12

Find the range of 4, 9, 6, 3, 2, 8, 10 and 11

Find the median of 2, 3, 7, 3, 4, 5, 8, 9, 9, 4, 5,3, 4, 2, 4 and 5

The mean of seven numbers is 96. If an eight number is added, the mean becomes 112. Find the eighth number.

The bar chart above shows the distribution of marks in a class test. If the pass mark is 5, what percentage of the students failed the test?

The grades of 36 students in a class test are as shown in the pie chart above. How many students have excellent?