Try plugging them in, might seem tedious, but it's the best way to practice. if you plug in a pair and the left side of the equation is less than or equal to 6, it's the right answer.

6 0

3 years ago

Read 2 more answers

A train travels 315 km in the same time that a car travels 265 km. If the train travels on average 20 km/h faster than the car,

aev [14]

Answer: 106 km/h,2.5 hr

Step-by-step explanation:

Given

The train travels 315 km in the same time car travels 265 km

The average speed of the train is 20 kmph faster than car

Suppose, speed of the car is v and it travels 265 km in t hours

$\therefore \dfrac{315}{v+20}=\dfrac{265}{v}\\\\\Rightarrow 315v=265\left (v+20\right)\\\\\Rightarrow 315v=265v+5300\\\Rightarrow 50v=5300\\\Rightarrow v=106\ km/h$

Time taken to travel is

$\Rightarrow t=\dfrac{265}{106}}\\\\\Rightarrow t=2.5\ h$

7 0

4 years ago

The sum of two numbers is twenty-one. One number is nineteen less than four times the other. Find the numbers.

KIM [24]

9514 1404 393

Answer:

8, 13

Step-by-step explanation:

The given relationships can be put into two equations. Let x and y represent the numbers.

x + y = 21 . . . . . their sum is 21

y = 4x -19 . . . . .one is 19 less than 4 times the other

Substituting for y in the first equation, we get ...

x + (4x -19) = 21

5x = 40 . . . . . . . . . add 19

x = 8 . . . . . . . . . . . divide by 5

y = 4(8) -19 = 13

The two numbers are 8 and 13.

7 0

3 years ago