Using the binomial expansion in the given expression we get,
72022+32022=(50−1)1011+(10−1)1011
=C01011(50)1011(−1)0+C11011(50)1010(−1)1+....C10111011(50)0(−1)1011+C01011(10)1011(−1)0+C11011(10)1010(−1)1+....C10111011(10)0(−1)1011
=5k−2
Using binomial expansion we get the remainder as −2+5=3