Question

The three consecutive numbers that we should start with to get 120 on the top are _______.

• A. 28, 29, 30
• B. 29, 30, 31
• C. 24, 25, 26
• D. 25, 26, 27

Answer 1

The correct option is B 29, 30, 31

Let three consecutive number in the bottom row be $x$, $x+1$, $x+2$.

Adding adjacent cell in the bottom row, we get

$x+(x+1)=2x+1$ ……(1)

$(x+1)+(x+2)=2x+3$ ……(2)

Adding (1) and (2) for the top most cell, we get

$(2x+1)+(2x+3)=4x+4$

Now we Know that,
$4x+4=120$
$4x=116$
$x=29$
$\therefore$ three successive numbers are : 29, 30, 31.