A 120-hp automobile engine delivers only 105 hp to the driving wheels of the car. What is the efficiency of the transmission and drive mechanism?

The efficiency of the transmission and drive mechanism is\(\square \)%

(Type a whole number or decimal rounded to two decimal places as needed.)

Multiply.

\( 1 \frac { 1 } { 4 } ft \times 1.3 ft = \square \)

(Round to the appropriate number of significant digits.)

Strontium-90\( ( ^ { 90 } Sr \)) is a by-product of nudear fission with a halk-life of approximately\( 28.9 yr \). After the chernobyl nudear reactor accident in 1986, large areas surrounding the site were contaminated with\( { } ^ { 90 } Sr \). If\( 5 \mu \)(micrograms) of\( { } ^ { 90 } Sr \)is present in a sample, the function\( A ( t ) = 5 ( \frac { 1 } { 2 } ) ^ { \frac { t } { 28.9 } } \)gives the amount\( A ( t ) \)(in\( \mu g\))present after t years. Evaluate the function for the given values of\( t \)and interpret the meaning in context. Round to 3 decimal places if necessary.

(a)\( A ( 173.4 ) \)

(b)\( A ( 57.8 ) \)

(c)\( A \)(289)

Their total bill for lunch was $56 . Toni paid the check with three twenty dollar bills. Write an algebraic expression that represents the difference between how much Toni paid and actual amount of bill. Do not simplify.

$\(\square \)Dollars

\(\frac { \sqrt { 7} - 5} { \sqrt { 5} + 5} = \square \)

(Simplify your answer. Type an exact answer, using radicals as needed.)