What is 25.4ml in scientific notation

When 142 is added to a number the result is 64 more times the number my options are 35 37 39 41

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.

Jimmy can run 3.5 miles in 20 minutes. how far can ne run in one hour and ten minutes?