You would expect 20 defective cell phones out of 550 cell phones.
Step-by-step explanation:
It is given that,
Therefore, it can be determined that 4 cell phones are defective for 110 cell phones tested.
Now, it was asked to find the number of cell phones that could be defective, if a total of 550 cell phones are tested.
To find the number of defective cell phones in 550 cell phones :
We know that, the rate of defective cell phones is 4 for 110.
Let us assume that, the number of defective cell phones be 'x' for 550.
To find x value :
Use the rate formula,
Rate = No.of defective cell phones / No.of cell phones tested
⇒ 4 / 110 = x / 550
Keep x alone on one side, and cross multiply 550 to the other side.
⇒ x = (550×4) / 110
⇒ x = 20 defectives
'x' is the number of defective cell phones in 550 cell phones tested.
Therefore, you would expect 20 defective cell phones out of 550 cell phones.