Element x is found in two forms: 90.0% is an isotope that has a mass of 20.0, and 10.0% is an isotope that has a mass of 22.0. what is the atomic mass of element x?
a. 20.0
b. 20.2
c. 20.8
d. 21.2
e. 21.8
can anyone explain this one for me?

What type of organic molecule comprises the majority of a potato?

Which of two curves exhibits exponential growth

What energy conversion occurs when a sling shot is used to shoot a rock across the room? (2 points) question 2 options: 1) stored mechanical energy is converted to mechanical energy. 2) stored mechanical energy is converted to radiant energy. 3) gravitational energy is converted to radiant energy. 4) gravitational energy is converted to mechanical energy.