A boy of 30 kg is carrying a load of 20 kg to the top of a building of height 13m . Find his total work done . If he can do it in 20 second calculate the power developed by him .​​

(urgent ) use pi 3.14 to estimate the circumference of the circle to the nearest hundredth middle is 4in (urgent )

You buy five cds at a sale for $5.95 each. write an expression for the total cost of the cds. then use the distributive property and mental math to evaluate the expression.

Scores on the cognitive scale of the bayley-scales of infant and toddler development range from 1 to 19, with a standard deviation of 3. calculate the margin of error in estimating the true mean cognitive scale score, with 99% confidence, if there are 12 infants and toddlers in a sample.