Which expression is equivalent to 9/10 ÷ 2/3. a. 9/3×2/10. b. 10/9×2/3 c. 10/9×3/2 d. 9/10×3/2

The answer is D.

First, you must know the fastest way to solve these types of expressions. 
For this example, the goal is to turn the divide symbol into a multiplication operation. Primarily, you have to take the reciprocal of the fraction you are dividing (the second one in the expression). This turns 2/3 into 3/2. Now, the equation reads 9/10 * 3/2.

If you would like to know how this works, let's do the equation together.
9/10 ÷ 2/3
If we turn the second fraction into the number one, then the first fraction divided by one (which equals itself) would be the answer. To do this task,
1 ÷ 2/3 = 3/2. So, we multiply 3/2 to each fraction.
(9/10 * 3/2) ÷ (2/3 * 3/2) 
27/20 ÷ 1 = 27/20 = 1 7/20

Answer is either b or c