# Difficult sequence

Here I go :

$3 + 5 + 6 = 15 \ 18 \ 72$
$5+ 5 + 6 = 25 \ 30 \ 94$
$5 + 6 + 7 = 30 \ 35 \ 85$
$5 + 5 + 3 = 25 \ 15 \ 73$
$9 + 4 + 7 = 36 \ 63 \ ?$

Replace ? with appropriate number

• Do you mean digit or number? – M Oehm Jul 14 '16 at 7:06

$29$

Explanation:

The formula is:
$a + b + c = a*b \quad a*c\quad ((a*b) + (a*c)) - c$

Take the example of the first row
$3 + 5 + 6 = 15$ $18$ $72$
Let $a = 3, b = 5 , c = 6$

$((3*5) + (3*6)) - 6 \Rightarrow (15 + 18) - 6 \Rightarrow 33 - 6 \Rightarrow 27$
Reverse of $27$ is $72$

In the same way for the last row
For $9 + 4 + 7 = 36$ $63$ $?$

$((9*4) + (9*7)) - 7 \Rightarrow (36 + 63) - 7 \Rightarrow 99 - 7 \Rightarrow 92$
reverse of $92$ is $29$

for the missing value

173.32

because

for the third column I get $$26.4 * a - 0.6*b + 7c -3.08ab$$

• I thinnk you are unnecessarily making it more difficult. – Hisenberg Jul 15 '16 at 2:36
• simpler or more complex is in the eye of the beholder. – Jasen Jul 15 '16 at 2:37