This is a system of equations question in disguise. First, locate a piece of information in this question that you can work with. "The sum of three numbers, a,b, and c, is 400 ," seems very straightforward. Write the equation a+b+c=400. Now the question tells you that "one of the numbers, a, is 40 percent less than the sum of b and c." Translate this piece by piece to get a=(1−0.4)(b+c), or a=0.6(b+c). Distribute the 0.6 to get a=0.6b+0.6c. Arrange these variables so they line up with those in the first equation as a−0.6b−0.6c=0. To solve for b+c, stack the equations and multiply the second equation by −1 :a+b+c=400−1(a−0.6b−0.6c)=0(−1)Now solve:Simplify by dividing both sides by 1.6 to get b+c=250. The correct answer is (D).