Let's start by seeing what percentage is incorrect. 100-85=15 So, 15% is incorrect when answering 3 problems wrong. So let's divide 15 by 3. 15÷3=5 So, each problem is worth 5%, let's divide 100 by 5. The reason I'm doing thiis is to find how many questions are on the quiz, since if you got them all right, it's 100. 100÷5 20 There are 20 questions, let's make sure this is correct. If she got 3 wrong, she got 17 right. Let's calculate her percentage and make sure it is the right one. 17÷20 .85×100 85% So, there are 20 questions on the math quiz.
<span>The area of the square is d^2. The area of the circle sandbox is πr^2=πd^2/4. So the area of play area only is equal to square area minus circle area which is d^2-πd^2/4.</span>