In first assignment of w1 i have passed all the tests
But still i am getting score of 50.
I checked everything in my code and everything is correct.
Sorry, but that means the code is not correct. There is a bug in the unit tests here that they do not catch the error if you forget to include the stride in your calculations for conv_forward and pool_forward. You can check if this is the problem by carefully examining your output values in the stride = 2 test case for pool_forward: they all need to agree, not just most of them.
The other thing that can cause this is coercing the output type of conv_single_step to be float32.