Aluminum and tin are both metals. The standard atomic weight for aluminum is 26.98. The standard atomic weight for tin is 118.71.Estimate the difference between the standard atomic weights of these two metals

92

Step-by-step explanation:

To estimate the difference between the standard atomic weights of these two metals we round up the given weights to the nearest whole number

The standard atomic weight for aluminum is 26.98.

To the nearest the whole number = 27

The standard atomic weight for tin is 118.71

To the nearest whole number = 119

Hence,

The estimated difference = 119 - 27

= 92

Probability that a failure is due to loose keys = 0.2376

Probability that a failure is due to improperly connected or poorly welded wires  0.078

Step-by-step explanation:

Given data:

P(A) = percentage of faulty electrical connections is 12% = 0.12

P(B) = mechanical defects is 88% =  0.88

P(C / B ) = percentage of defects that are related to loose keys is 27% =  0.27

P( D/B ) = improper assembly is 73% = 0.73

P(E/A) =  defective wires  is 35% =  0.35

P( F/A)= improper connections is 13% =  0.13

P( G/A ) = percentage of poorly welded wire is 52% = 0.52

a) Probability of being failure because of loose keys = 0.27\times 0.88 = 0.2376

b) Improperly connected = 0.13\times 0.12 = 0.0156

    poorly welded wires= 0.52 \times 0.12 = 0.0624

Probability of being failure because of improperly connected or poorly welded wires = 0.0156 + 0.0624 = 0.078