A cycle dealer offers a discount of 10% and still makes a profit of 26%.

Given,

MP of the cycle $=$ Rs. 840

Discount $=10 \%$

So, $\mathrm{SP}=\mathrm{MP} \times\left(\frac{100-\text { Discount } \%}{100}\right)$

$=840 \times\left(\frac{100-10}{100}\right)$

$=$ Rs. 756

Now, SP $=$ Rs. 756 and Gain $=26 \%$

So, $\mathrm{CP}=\frac{100}{100+\text { Gain } \%} \times 756$

$=\frac{100}{126} \times 756$

$=$ Rs. 600

Hence, the actual cost of the cycle is Rs. 600 .