Question

A rectangular field of length 320 m and breadth 245 m has two roads in the middle of it, 5 m wide running at
right angles to each other, one is along the length and the other along the breadth. Find the area of the roads.​

Answer 1

Answer:

This is a classic example of finding mean and standard deviation using Z values.

From this page find the Z value corresponding to 31% area under the curve and 92% (100-8) percent area under the curve.

Math Is Fun Virtual Manipulative

Note: You'll probably be given tables to lookup in your quizzes.. they're a bit confusing. But you might as well learn how to use it.

As you know:

Z=X−μσZ=X−μσ

Put in X and Z values values twice, you'll have two linear equations. Solve them and the answer is yours!