Two cars left the same town traveling in the same direction. Car A traveled 40 miles per hour and left at 3:20. Car B traveled 50 miles per hour and left at 4:40. At what time will car B catch up with car A ？（）

A child withdraws from his piggy bank 10% of the origin...

单项选择题A child withdraws from his piggy bank 10% of the original sum in the bank. If he must add 90￠ to bring the amount in the bank back up to the original sum, what was the original sum in the bank ？（）

The width of a rectangle is 6 cm less than the length. ...

单项选择题The width of a rectangle is 6 cm less than the length. If the perimeter of the rectangle is 48 cm, what is the length of the rectangle in centimeters ？（）

A box contains 100 balls, numbered from 1 to 100. If th...

单项选择题

A box contains 100 balls, numbered from 1 to 100. If three balls are selected at random and with replacement from the box, what is the probability that the sum of the three numbers on the balls selected from the box will be odd ？（）