The third plant is planted in the same soil as the others, but it receives only light and water. After 2 weeks, it is 6 centimeters tall. If it continues
growing at this rate, how tall will it be after 6 weeks?please help

The ratio is 2 weeks:6 centimeters, so let’s simplify: To know how much it grew in ONE week, we need to divide by 2, so 2/2=1 and 6/2=3 so the ratio now is 1:3 now, we multiply those by the number of weeks: 6. So 1x6=6 and 3x6=18 the ratio is 6:18. The plant will be 18 centimeters after 6 weeks