The answer is 7b+35 because the seven multiplies by the b and the 5 meaning that you multiple the number that’s on the outside with what’s on the inside and be b is a variable it cannot be multiplied so you combine 7 and b which gives you 7b and then you multiply 7 and 5 which gives you 35
Okay, so let's find the actual failure rate first. 6/1000 times 100 (to give over a 100%) equals to 0.6. The actual failure rate is 0.6%. The theoretical probability is 0.2% 0.6-0.2=0.4. The difference is 0.4%. Hope that helped!
