Mark and his family went out for dinner for his birthday. The cost of the meal before sales tax was $65.50. The family decides to tip 20% for the good service they received. What tip did Mark pay

$78.6

Step-by-step explanation:

Cost of meal before pay tax = $65.50

If the family decide to tip 20% of the amount of mean for good service, amount tipped will be;

20% of $65.50

= 20/100 × 65.50

= 0.2×65.50

= $13.1

Amount tipped = $13.1

Total amount paid my mark = original cost of food + tip

Total amount paid by mark = $65.5+$13.1

Total amount paid by mark = $78.6

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)