Answer:
See below ~
Step-by-step explanation:
P (first red) :
⇒ Original number of red balls / Total
⇒ 4 / 10
⇒ 0.4
⇒ 40%
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Remember the first ball drawn is NOT replaced.
P (second red) :
⇒ Original number of red - 1 / Total - 1
⇒ 4 - 1 / 10 - 1
⇒ 3/9
⇒ 33%