To get the final price of a chair we have to find 40% of 210, subtract it from 210. Then find 140% of it and it will be the result.
Lets do this
40%=0.4
0.4*210=84$
Now we have to calculate increased price, so 100%+40%=140%
140%=1.4
1.4*84=117.6$ - its the final price of a chair.