Write the missing numbers so that 2a + 5b = 30

2a + 5b = 30 when a=0 and b= 6

2a + 5b = 30 when a=5 and b=

2a + 5b =30 when a=15 and b=

i really have no clue on how to do this and i need the answer really quickly!

Me because some of question i don’t understand

16. you're planning to buy a boat, a motor, and some miscellaneous boating equipment. the boat costs $325, the motor costs $225, and the equipment costs $79. if you've saved $438 toward these purchases, how much more do you need to save? a. $181 b. $281 c. $291 d. $191

Solve this riddle: i am an odd number. i an less than 100. the some of my digit is 12. i am a multiple of 15. what number am i?