algebra

posted by Bri

1.a certain two-digit number has a value that is seven more than six times the sum of its digits. the tens digit is 3 more than the units digit. find the number

2.In Colorado Creek, Darrell can row 24km downstream in 6 hours or he can row 18km upstream in the same amount of time. find the rate he rows in still water and the rate of the current.

3. if the temperature on a Celsius scale is divided by five it is equal to the reading on a Fahrenheit scale. fifteen times the Fahrenheit reading is equal to three times the Celsius reading. please find the temperature on each scale.

1. Dallas

2.) distance = time × speed

Let rowing speed in still water be x, current in river be y

Downstream, speed is his natural rowing speed plus the current:
24 = 6(x + y)

Upstream, speed is natural rowing speed minus current:
18 = 6(x - y)

or
4 = x + y
3 = x - y

7 = 2 x

x = 7/2 km/h (and current is 1/2 km/h)

He can row at 3.5 km/h

Similar Questions

1. math

This is an SAT question of the day that I can't understand. The sum of the digits of a three-digit number is 12. If the hundreds digit is 3 times the tens digit and the tens digit is 1 over 2 the units digit, what is the tens digit …
2. Algebra math.

1) the sum of the digits of a two digit number is 9. The value of the number is 12 times the tens digit. Find the number. 2) the sum of the digits of a two digit number is 12. If 15 is added to the number the result is 6times the units …
3. word problem

the different between the digit of a two digit number is 1, the number it self is 1 more than 5 times the sum of the digits, if the unit digit is greater than the tens digit, find the number.
4. word problem

the different between the digit of a two digit number is 1, the number it self is 1 more than 5 times the sum of its digits, if the unit digit is greater than the tens digit, find the number.
5. Math

The mystery number's tens digit is less than the ones digit. The tens digit is less than the tenths digit. The tens digit is even. Its ones digit divided by its tens digit is 5. The product of two of the digits is 6 It has two odd …
6. algebra

1. If the units digit of a two digit number is six more than the tens digit and the number is eight more than twice the sum of the digits, what is the number?
7. basic algebra

the tens digit of a certain number is 4 more than the units digit. the sum of the squares of the two digits is 26. find the number.
8. Algebra

In a two-digit number the units’ digit is 7 more than the tens’ digit. The number with digits reversed is three times as large as the sum of the original number and the two digits. Find the number.