A steel manufacturer is testing a new additive for manufacturing an allow of steel. The joint probability mass function of tensile streanth and additive concentrative is

concentration additive tensile strength 100 150 200

.02 .05 .06 .11

.04 .01 .08 .10

.06 .04 .08 .17

.08 .04 .14 .12

I've figured out the marginal probability mass functions but am having trouble with 2 other questions.

Given that a specimen has an additive concentration of .04, what is the probability that it's strength is 150 or more?

Find µx and µy.

THANK YOU!