Question

#3 and 4, show work please

Answer 1

Question 3: 2.7 hours

Question 4: 2.3 hours

Explanation:

Question 3:

Time taken by 1st delivery driver = t1 = 6 hours

Time taken by 2nd delivery driver = t2= 5 hours

Time together = T

`{( 1 )/( T ) = ( 1 )/( t1 ) + ( 1 )/( t2 )}`

`{( 1 )/( T ) = ( 1 )/( 6 ) + ( 1 )/( 5 )}`

`{( 1 )/( T ) = 0.166+0.2 = 0.366}`

`{T = ( 1 )/( 0.366 ) = 2.732}`

Rounded to the nearest tenth: 2.7 hours

Question 4:

The first valve takes 4 hours to completely drain = t1

`\mathrm{Rate\:for\:first\:valve\:will\:be\:(1)/(4)\:per\:hour}`

The second valve taken 5.25 hours to completely drain = t2

`\mathrm{Rate\:for\:second\:valve\:will\:be\:(1)/(5.25)\:per\:hour}`

Combined time = T

`{( 1 )/( T ) = ( 1 )/( t1 ) + ( 1 )/( t2 )}`

`{( 1 )/( T ) = ( 1 )/( 4 ) + ( 1 )/( 5.25 )}`

`{( 1 )/( T ) = 0.25+0.190 = 0.44}`

`{T = ( 1 )/( 0.44 ) = 2.272}`

Rounded to the nearest tenth: 2.3 hours