Henry drives 2 km in the first 10 minutes. After every 10 minutes he increases his speed and travels 1 km farther in the next 10 minutes than in the preceding 10 minutes. How many kilometres does he travel in one hour?
Three 5-Star bars, two Kit Kat bars and one Perk bar cost 145 dollars. Two Kit Kat bars, one 5-Star bar and three Perk bars cost 135 dollars. Find the combined price, in dollars, of one bar of each kind.
Roy walks the first 10 m of his journey to school, then travels the remaining three-fourths of the whole journey by bus. How far is his school from his house?
A fruit vendor bought 4 dozen apples at 60 dollars per dozen and sold every apple for 6 dollars. How much was his gain, in dollars? Count only the stated buying and selling prices.
Veena watches a movie on Netflix. She stops after watching one-third of it. If she had watched 12 minutes more, she would have watched half of the movie. How long is the movie, in minutes?
Frank has more than 20 and fewer than 70 marbles. If he makes piles of 4, one marble is left over. If he makes piles of 7, three marbles are left over. How many marbles does he have?
Each term of a sequence is found by subtracting the same number from the preceding term. The first term is 257 and the fifth is 209. What is the fifteenth term?