The result of which expression will best estimate the actual product of (-4/5)(3/5)(-6/7)(5/6)

a (-1)(1/4)(-1)(-1)
b(-1)(1/2)(-1)(-1)
c(-4/2)(3/2)(-2/5)(5/2)
d(3-/4)(3-/4)(-1/5)(1/2)

16 more than the product of 5 and p

Two times a number plus three times another number equals 4. three times the first number plus four times the other number is 7. find the numbers

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?