Question 760023
He made 40% profit
Let {{{ x }}} = the amount the vendor paid
{{{ 1 = x + .4x }}}
{{{ 1.4x = 1 }}}
{{{ x = .7143 }}}
This is the price the vendor would have paid for 
{{{ 10 }}} bananas
I can make the ratio:
{{{ .7143 / 10 = 1 / y }}}
{{{ .7143y = 10 }}}
{{{ y = 14 }}}
He paid 1 Re for 14 bananas