A tricycle is sold at a gain of 16%.

Let the S. P of the tricycle be Rs. $x$ and C.P be Rs. $y$

Gain $\%=16 \%$

$S \cdot P=C \cdot P\left(\frac{100+\text { gain } \%}{100}\right)$

Then we have,

$x=y+\left(\frac{y \times 16}{100}\right)$

$x=y+0.16 y$

$x=1.16 y$

When S.P increases by Rs. 100 , we get

$\Rightarrow x+100=y+\left(\frac{y \times 20}{100}\right)$

Put ting $x=1.6 y$, we get

$\Rightarrow 1.16 y+100=y+0.2 y$

1. $16 y+100=1.2 y$

$0.04 y=100$

$y=\frac{100}{0.04}$

$=2500$

Thus, C.P of the tricycle $i s$ Rs. 2500 .