83, 89, and 97 are three primes between 80 and 100.
The primes between 30 and 50 are 31, 37, 41, 43, and 47, all of which are odd. All other numbers between 30 and 50 are composite.
To mentally find 2*50*25, you could either first multiply 25 by 2, to get 50*50, which can easily be calculated as 2500, or you could multiply the 50 by 2, for a result of 100*25, which is clearly also 2500.
The first thing you should know are properties of exponents to solve the problem. For this case the radical form is given by the writing of the expression in the form of root. We have then: t^-3/4 =4^root(t^-3)=4^root ((1)/(t^3)) answer t^-3/4=4^root((1)/(t^3))
