If $a/b=2$, $b/c=3$, $c/d=4$, $d/e=3$, $e/f=2$ and $f/g=1\cdot5$, what is the value of $\frac{a+b+c}{e-f+g}$?

To solve this, work backwards by assigning a convenient value to the last variable, g. Let g = 2. Using the given ratios: f = 1.5 × 2 = 3 e = 2 × 3 = 6 d = 3 × 6 = 18 c = 4 × 18 = 72 b = 3 × 72 = 216 a = 2 × 216 = 432 Now, substitute these values into the target expression: Numerator (a + b + c) = 432 + 216 + 72 = 720 Denominator (e - f + g) = 6 - 3 + 2 = 5 Result = 720 / 5 = 144.