a cylindrical tank is a diameter of 14 m and a height of 3.5 m find the capacity of the water tank in litres

Ineed to know the answer to this algebra question.

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.

Evaluate 5 + 6 · 2 – 8 ÷ 4 + 7 using the correct order of operations. a. 22 b. 11 c. 27 d. 5