Two-ni that less than the product of 1 2/5 and b is 1 less than 2 1/2 of b
no idea what two-ni means, but
the product of 1 2/5 and b is 1 less than 2 1/2 of b
can be written as
(1 2/5)b = (2 1/2)b - 1
maybe you can take it from there...
the product of 1 2/5 and b is 1 less than 2 1/2 of b
can be written as
(1 2/5)b = (2 1/2)b - 1
maybe you can take it from there...