What gives the value of this expression -20/-4+(-15) (-2)

Can you simplify 4/7? 24 points will be awarded!

Successful implementation of a new system is based on three independent modules. module 1 works properly with probability 0.96. for modules 2 and 3, these probabilities equal 0.95 and 0.90. compute the probability that at least one of these three modules fails to work properly.

The first floor of marcus’ house is 1,440 square feet. he will cover 1,033 square feet with wood and the rest with tile. a box of tiles will cover 11 square feet. how many boxes of tile does marcus need to buy to cover the floor?