Hat is the simplified form of 24r-3( 2r-5t)-4t?

A car travels for 4(t+3) hours at a constant speed of 10(t+3) km/h. If the total distance travelled by the car is 810 km, find t

IceJOKER [234]

Step-by-step explanation:

$\because \: time \times speed = distance \\ \therefore \: 4(t + 3) \times 10(t + 3) = 810 \\ \therefore \: 4(t + 3)^{2} = 81 \\ \therefore \: \{2(t + 3) \}^{2} = {9}^{2} \\ \therefore \: \{2(t + 3) \} = {9} \\ \therefore \: t + 3 = \frac{9}{2} \\ \therefore \: t = \frac{9}{2} - 3 \\ \therefore \: t = \frac{9 - 6}{2} \\ \therefore \: t = \frac{3}{2} \\ \therefore \: t = 1.5 \: hrs \\$

$\because \: time \times speed = distance \\ \therefore \: 4(t + 3) \times 10(t + 3) = 810 \\ \therefore \: 4(t + 3)^{2} = 81 \\ \therefore \: \{2(t + 3) \}^{2} = {9}^{2} \\ \therefore \: \{2(t + 3) \} = {9} \\ \therefore \: t + 3 = \frac{9}{2} \\ \therefore \: t = \frac{9}{2} - 3 \\ \therefore \: t = \frac{9 - 6}{2} \\ \therefore \: t = \frac{3}{2} \\ \therefore \: t = 1.5 \: hrs \\ speed \: of \: car = 10(t + 3) \\ \hspace{60 pt} = 10(1.5 + 3) \\ \hspace{60 pt}= 10 \times 4.5 \\ \red{ \boxed{ \bold{ \therefore \: speed \: of \: car = 45 \:km/ h}}} \\$

3 0

2 years ago

A student obtain 85 ,90,95,100and 75 in his maths test (1). What is the average of his test grades?

netineya [11]

Answer:

89.

Step-by-step explanation:

There are 5 scores.

So the Average = (85 + 90+95+100+ 75)/5

= 445/5

= 89.

8 0

1 year ago

Read 2 more answers

Mr. Singh just left his house to go to work and has a meeting as soon as he arrives. The

vodomira [7]

Answer:5

Step-by-step explanation:

3 0

2 years ago

Samantha received an allowance of $3 every week. By babysitting, she earned $30 every week. How much did Samantha have in four w

kvasek [131]

Okay, so there are 4 weeks in a month. 30x4 is 120,and 3x4 is 12. Add the 2 together and you have 132$

6 0

2 years ago

Setup a rational equation and solve it from the word problem. Mr. Solberg can ride his scooter 3 miles against the wind in the s

dolphi86 [110]

Answer:

The speed of Mr Solberg's scooter when there is no wind is 35 miles per hour

Step-by-step explanation:

The given parameters are;

The time Mr. Solberg rides his scooter and cover 3 miles against the wind = The time Mr. Solberg rides his scooter and cover 4 miles with the wind

The speed of the wind = 5 miles per hour

Let v, represent the speed of Mr Solberg's scooter when there is no wind, we have;

Time = Distance/Speed

Mr Solberg's speed against the wind = v - 5

Mr Solberg's speed with the wind = v + 5

The distance covered at a given time, while riding against the wind = 3 miles

The distance covered at the same time, while riding with the wind = 4 miles

The time in both instances are therefore 3/(v - 5) = 4/(v + 5)

From which we have;

3 × (v + 5) = 4 × (v - 5)

3·v + 15 = 4·v - 20

20 + 15 = 4·v - 3·v

4·v - 3·v = 20 + 15

v = 35

The speed of Mr Solberg's scooter when there is no wind = v = 35 miles per hour.

7 0

2 years ago