Question

Anita wants to enter a number into each small
triangular cell of the triangular table. The sum
of the numbers in any two such cells with a
common side must be the same. She has
already entered two numbers. What is the sum
of all the numbers in the table?
A) 19
B) 20
C) 21
D) 22​

Answer 1

Answer:

The answer is option (C) 21.

Step-by-step explanation:

Sum of the no. in the triangle

= 2 × 6 + 3 × 3

= 12 + 9 = 21  

Consider in a triangle there are three other smaller triangles. The number she has already entered are 2 and 3. So she will add number 2 six times into the triangle and number 3 three times into smaller triangles. Therefore the sum of the numbers is 21.