Formulas You’ll Need for the GMAT™ Quantitative Section’s Statistics and Problem Solving Questions

When you’re solving problems in the GMAT™ Quantitative Section, you need to be both fast and accurate. You cannot choose just one. If you want to ace the test, you’ll need to be able to understand the problem quickly, figure out the process to solve it, and actually perform the necessary calculations in less than 2 minutes. There are 31 questions in all and just 61 minutes to solve them.

To achieve that, you need to have the equations you need ingrained in your brain, and we have the resources you need. In the following chart, you’ll find the essential equations for the GMAT™ Quantitative Section Statistics and Problem Solving Questions. You’ll find formulas relating to the other types of questions on this section of the test here:

Arithmetic and Geometry

Algebra

Use them to solve our free sample problems.

For more in-depth information, check out our free study guide

Statistics and Problem-Solving

Category	Formula	Symbols	Comment
Statistics and Problem Solving	\(d=r \cdot t\) \(w=r \cdot t\) \(W=r \cdot t\)	d = distance w = wage W = Work done r = rate t = time
Statistics and Problem Solving	\(TW=WA+WB\)	TW = Total work done WA = Work done by A WB = Work done by B	Combined Work
Statistics and Problem Solving	\(\dfrac{1}{t} = \dfrac{1}{tA} + \dfrac{1}{tB}\)	t = total time tA = time consumed by A tB = time consumed by B	Combined Work
Statistics and Problem Solving	\(Du=Su \cdot \dfrac{Du}{Su}=Su \cdot CF\)	Du = Desired Unit Su = Starting Unit CF = Conversion Factor	Multiple steps may be needed.
Statistics and Problem Solving	\(a \cdot b\% =a \cdot \frac{b}{100}\)	a = any real number b% = any percent	Remember to simplify if necessary
Statistics and Problem Solving	\(\% = \frac{\vert b-a \vert }{b} \cdot 100= \frac{c}{b} \cdot 100\)	% = % increase or decrease a = new value b = original value c = amount of change
Statistics and Problem Solving	\(\overline{x}= \dfrac{\Sigma x_i}{n}\)	\(\overline{x}\) = mean \(x_i\) = value of each measurement n = number of measurements
Statistics and Problem Solving	\(Md=(\dfrac{n+1}{2})^{th} term\)	Md = median n = number of measurements (odd)
Statistics and Problem Solving	\(Md=\dfrac{(\frac{n}{2})^{th} term + (\frac{n+1}{2})^{th} term }{2}\)	Md = median n = number of measurements (even)
Statistics and Problem Solving	\(s=\sqrt{\Sigma(x_i-\overline{x})^2/(n-1)}\)	s = standard deviation \(\overline{x}\) = mean \(x_i\) = value of each measurement n = number of measurements
Statistics and Problem Solving	\(V=s^2\)	v = Variance s = standard deviation
Statistics and Problem Solving	\(CV=RSD=100 \cdot \dfrac{s}{\overline{x}}\)	CV = Coefficient of variation RSD = Relative standard deviation s = standard deviation
Statistics and Problem Solving	\(P(n, r)=\dfrac{n!}{(n-r)!}\)	P = number of permutations n = total number of objects r = number of objects to be chosen
Statistics and Problem Solving	\(C(n, r) = \dfrac{n!}{r! \cdot (n-r)!}\)	C = number of combinations n = total number of objects r = number of objects to be chosen
Statistics and Problem Solving	\(p = \dfrac{d}{t}\)	p = probability of an event d = number of ways desired event can occur t = total number of possible events
Statistics and Problem Solving	\(x_n = x_1 + d(n-1)\)	\(x_n = nth\) element of an arith. sequence \(x_1 = 1st\) element of an arith. sequence d = common difference	Arithmetic Sequence
Statistics and Problem Solving	\(x_n = x_1 \cdot r^{(n-1)}\)	\(x_n = nth\) element of a geom. sequence \(x_1 =\) first element of a geom. sequence d = common difference	Geometric Sequence
Statistics and Problem Solving	\(SI = P \cdot IR \cdot t\)	SI = Simple Interest P = Principal (amount borrowed) IR = Interest Rate t = time (in same units as IR)
Statistics and Problem Solving	\(A_{SI} = P + SI = P \cdot (1+(IR \cdot t))\)	\(A_{SI}\) = Future value to be paid (for SI) P = Principal (amount borrowed) SI = Simple Interest IR = Interest Rate t = time (in same units as IR)
Statistics and Problem Solving	\(A_{CI} = P \cdot (1 + \frac{IR}{n})^{n \cdot t}\)	\(A_{CI}\) = Future value to be paid (for CI) P = Principal (amount borrowed) IR = Interest Rate n = Number of times interest is compounded per unit of time t = time (in same units as IR)