We need to call for x minute + Phone Company A charges a monthly fee of $42.50, and $0.02 for each minute talk time. So we have to spend: <span>$42.50+ $0.02x + </span>Phone company B charges a monthly fee of $25.00, and $0.09 for each minute of talk time. So we have to spend: <span>$25.00+ $0.09x
We solve for x: </span>$42.50+ $0.02x> <span>$25.00+ $0.09x or </span>$42.50- $25.00 > $0.09x- <span>$0.02x and we have $0.07x<$27.50 or x< 27.50:0.07 and x< 393.86
The answer is: If we have to call much time, at least 394 minutes, we should choose A If not, choose B</span>
We have to write the standard form of : two hundred ten million, sixty four thousand , fifty. 210 * 10,000,000 + 64 * 10,000 + 50 Answer: The standard form is 210,064,050.