A banana costs three times as much as an apple. The total cost of 1 banana and 1 apple is $1.60. if a represents the cost of one apple, which equation could you use to find a?

A: a/4 = 1.60
B: 3a = 1.60
C: a = a = 1.60
D: 3a + a = 1.60

He weights of 2-pound bags of best dog food are approximately normally distributed with a given mean  and standard deviation  according to the empirical rule, what percentage of the bags will have weights within 3 standard deviations of the mean? 47.5%68%95%99.7%

Aadc is formed by reflecting aabc across line segment ac, as shown in the figure. if the length of ac is 4 units, the area of aadc is square units.

Aclassroom is made up of 11 boys and 14 girls. the teacher has four main classroom responsibilities that she wants to hand out to four different students (one for each of the four students). if the teacher chooses 4 of the students at random, then what is the probability that the four students chosen to complete the responsibilities will be all boys?