Question

If a+b+c+d=63
then what is ab+bc+cd ?
No Calculas...
You can use geometry or algebra
Your wish..​

Answer 1

Answer:

Step-by-step explanation:

Given  

If a+b+c+d=63 then what is ab+bc+cd  

From the figure we need to maximize the shaded portion area that is ab + bc + cd, so we need to minimize the area of non shaded part = ad. So we need to assign minimum positive numbers to both a and d.

 so consider a = d = 1.(maximizes only two numbers)

So maximum values of b and c will be 31 and 30 in any order.

So ab + bc + cd  

= 1 x 31 + 31 x 30 + 30 x 1

= 31 + 930 + 30

= 991